When first initializing, recent-block controller now back-fills up to
its desired history length. This makes estimated gas prices reflect a
longer recent history, even when first switching to a new network.
Fixes#2925
Fixed warnings:
```md
app/scripts/controllers/computed-balances.js
+ 35:27 warning Missing space before function parentheses space-before-function-paren
+ 41:14 warning 'address' is never reassigned. Use 'const' instead prefer-const
+ 61:9 warning 'updater' is never reassigned. Use 'const' instead prefer-const
+ 68:11 warning 'newState' is never reassigned. Use 'const' instead prefer-const
app/scripts/controllers/network.js
+ 104:29 warning Missing space before function parentheses space-before-function-paren
app/scripts/lib/createLoggerMiddleware.js
+ 4:32 warning Missing space before function parentheses space-before-function-paren
+ 15:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/createOriginMiddleware.js
+ 4:32 warning Missing space before function parentheses space-before-function-paren
+ 9:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/createProviderMiddleware.js
+ 5:34 warning Missing space before function parentheses space-before-function-paren
+ 13:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/events-proxy.js
+ 1:50 warning Missing space before function parentheses space-before-function-paren
+ 31:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/nodeify.js
+ 2:22 warning Missing space before function parentheses space-before-function-paren
+ 2:24 warning Missing space before opening brace space-before-blocks
+ 5:18 warning Missing space before function parentheses space-before-function-paren
+ 5:20 warning Missing space before opening brace space-before-blocks
app/scripts/lib/pending-balance-calculator.js
+ 16:19 warning Missing space before function parentheses space-before-function-paren
app/scripts/lib/pending-tx-tracker.js
+ 85:11 warning '||' should be placed at the end of the line operator-linebreak
+ 87:11 warning '||' should be placed at the end of the line operator-linebreak
+ 88:11 warning '||' should be placed at the end of the line operator-linebreak
+ 90:11 warning '||' should be placed at the end of the line operator-linebreak
+ 91:11 warning '||' should be placed at the end of the line operator-linebreak
app/scripts/lib/port-stream.js
+ 3:22 warning Missing space before function parentheses space-before-function-paren
+ 3:24 warning Missing space before opening brace space-before-blocks
app/scripts/lib/tx-gas-utils.js
+ 84:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/tx-state-history-helper.js
+ 12:37 warning Missing space before function parentheses space-before-function-paren
+ 23:30 warning Missing space before function parentheses space-before-function-paren
+ 30:23 warning Missing space before function parentheses space-before-function-paren
+ 35:28 warning Missing space before function parentheses space-before-function-paren
+ 41:2 warning Newline required at end of file but not found eol-last
app/scripts/lib/tx-state-manager.js
+ 94:13 warning 'value' is never reassigned. Use 'const' instead prefer-const
ui/app/reducers.js
+ 45:7 warning 'state' is never reassigned. Use 'const' instead prefer-const
+ 53:7 warning 'stateString' is never reassigned. Use 'const' instead prefer-const
ui/lib/tx-helper.js
+ 27:2 warning Newline required at end of file but not found eol-last
ui/app/components/account-dropdowns.js
+ 163:1 warning More than 2 blank lines not allowed no-multiple-empty-lines
ui/app/components/menu-droppo.js
+ 22:7 warning 'style' is never reassigned. Use 'const' instead prefer-const
ui/app/components/shapeshift-form.js
+ 135:11 warning '&&' should be placed at the end of the line operator-linebreak
ui/app/components/typed-message-renderer.js
+ 35:25 warning Missing space before function parentheses space-before-function-paren
+ 42:2 warning Newline required at end of file but not found eol-last
mascara/server/index.js
+ 11:42 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 12:36 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 13:33 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 14:40 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 20:29 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 21:29 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
+ 26:40 warning Use path.join() or path.resolve() instead of + to create paths no-path-concat
```
