feat(i18n): replace IDL and its family with i18n module

- add i18n module with the following public interface:
  - addLanguage
  - setLanguage
  - detectLanguage
  - setFallbackLanguage
  - t
  - IDL (deprecated, compatible with old window.IDL)

- split languages from source/legacy/i18n.js into source/i18n/*.litcoffee

- update all uses of IDL (just replace with app.i18n.IDL for now),
direct uses of vk_lang and vk_lang_* (replace with app.i18n.t )

- replace IDL("nonexistent-key") with "nonexistent-key" for all such keys

- IMPORTANT: do not let user choose the language. Always
use site language

- detect site language in VkOptMainInit like so:
app.i18n.detectLanguage( window.vk.lang );

- do not save language on server or in cookies (was "vklang" cookie)

This closes #111.
fix(photo): from vk_ph_comms remove copypasted "params.v" lines

Remove accidentally copypasted "params.v = 3.0" lines from
vk_ph_comms.get_data() in legacy/vk_media.js

This closes #117.
refactor(init): don't check for some "old vkopt dislike plugin"

That was a deprecated check during installation.

This closes #118.
refactor(init): don't check for VkOpt 1.x

VkOpt 1.x died in 2011. I think it's time to move on.

This closes #119.
feat(init): auto-reload during installation, don't show popup

This closes #78, related to #86, related to #68.
refactor(init): remove deprecated things from InstallRelease()

In InstallRelease():

- don't check window.lastWindowWidth, it was needed to
correctly show pop-over with warnings. Installation goes
just fine without it. See #122

- don't set "VK_SAVE_MSG_HISTORY_PATTERN". See #123

- don't check window.IDBit, it was used in VkOpt 1.x. User could
hardcode his settings to IDBit variable somewhere in scripts
not to fear cookie cleaning. See #120

- remove deprecated "vkplayer" cookie. That one was some time ago
needed to control audio player. See #121

- in vkLoadSettingsFromServer() invoke callback in non-check mode too.
Finish installation after loading remote settings backup when
doing fresh install

This closes #120, closes #121, closes #122, closes #123.
chore(meta): change name to "vk-x"

Change project name to "vk-x" in package.json, README.md, gulpfile.litcoffee
At this moment the project is being transferred to vk-x organization.

This is related to #20.