Refactor l10n. Fix #363

Helpful links:

- <https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIStringBundleService>
- <https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIStringBundle>
- <https://github.com/adblockplus/adblockplus/blob/03b965c743f7688622b75b0e7525a17913d7e0ea/chrome/content/ui/i18n.js>
Merge pull request #365 from lydell/refactor-l10n

Refactor l10n. Fix #363
Fix #366: Allow autofocus when switching back to a tab

If a text input is focused and you switch to another window or tab
Firefox blurs the text input. When you switch back to the tab, Firefox
automatically focuses the text input again. Those focus events should be
allowed.
Merge branch 'develop' of github.com:akhodakivskiy/VimFx into develop
Localize to ja(Japanese)
Merge pull request #369 from pluser/localize_ja

Add Japanese localization
Merge pull request #367 from lydell/autofocus-tab-switch-back

Fix #366: Allow autofocus when switching back to a tab
Release v0.5.14
Fix typo in changelog
Suppress non-hintchars key presses in hints mode

They used to be passed along to the browser, which could confusingly
activate site commands, as described in #371.
Add CONTRIBUTING.md
Merge branch 'develop'
Re-add `<em:type>` to install.rdf

It isn’t needed for extensions and themes, but AMO reviews strongly
recommend it anyway.
Add missing style rules
Improve coding style

- Almost all code is now wrapped at 80 chars, except a few special cases
  such as the `commands = [...]` block in commands.coffee. I didn’t
  bother to go through help.coffee and window-utils.coffee too much
  since they need rewrites anyway.
- Consistent use of parenthesis when calling functions.
- Consistent use of single quotes over double quotes.
- Consistent spacing.
- Removed unused or unnecessary code.
- Refactored unload.coffee into unloader.coffee, which should be easier
  to understand.
- Comments are now full sentences.
- This also fixes a few very minor bugs.

I’ve deliberately left out mode-hints/{hints,marker}.coffee to avoid
large merge conflicts with #330.
Fix #348: Make f always open links in the same tab

By temporarily removing `target="_blank"` from links when
simulating clicks on them.
Merge pull request #384 from zhuochun/issue-348-link-target

Make `f` always open links in the same tab
Fix #393, #380: Don’t suppress Esc in browser chrome
Fix #308: Don’t use modifiers in default key bindings
Fix #385: Support counts