* feat: add app.getSystemLanguage() API
* Change the API to getPreferredSystemLanguages
* Fix test
* Clarify docs and add Linux impl
* Remove USE_GLIB
* Don't add C to list
* Remove examples since there's a lot of edge cases
* Fix lint
* Add examples
* Fix compile error
* Apply PR feedback
* Update the example
* docs: add references to app.whenReady() in isReady
* refactor: prefer app.whenReady()
In the docs, specs, and lib, replace instances of `app.once('ready')`
(seen occasionally) and `app.on('ready')` (extremely common) with
`app.whenReady()`.
It's better to encourage users to use whenReady():
1. it handles the edge case of registering for 'ready' after it's fired
2. it avoids the minor wart of leaving an active listener alive for
an event that wll never fire again
* infrastructure for setLocale via klang
* add documentation for setLocale
* add test for setLocale
* fix spec
* add spec and update docs
* fix carriage feeds on windows
* SetLocale() sets LC_ALL on Linux
* in SetLocale() on Linux, use g_setenv()
* fix tyop: '#ifdef OSX_POSIX'
* make the linter happy
* improvements from review
