Only leave translations that are 90+% complete. This means the dropped
ones won't be installed, but (as with Qt client) will still be there in
the repo to avoid the need in adding them back if/when the time comes.
* Reformat CMake code
* Bump minimum CMake version to 3.12
* Add target sources separately via `target_source()`
* Make `tr_win32_app_info()` add target sources on its own
* Don't use `include_directories()`
* Don't use `add_definitions()`
* Limit use of `add_compile_options()`
* Move VDKQueue target declaration to a subdirectory
* Add `tr_disable_source_files_compile()` helper
* Add `tr_target_glib_resources()` helper
* Add `tr_gettext_msgfmt()` helper
* Enable AUTOUIC for Qt client
* Enable AUTORCC for Qt client
* Remove AUTO{MOC,RCC,UIC} source group overrides
* Add `tr_target_idl_files()` helper
* Move source group setup to `tr_qt_add_translation()`
* Add `tr_target_xib_files()` helper
* Prefer `target_sources()` to intermediate variables
* Use explicit visibility versions of `target_*()` commands
* Prefer genexes to conditions in `target_*()` commands
* Add `tr_allow_compile_if()` helper
* Leave only top-level `project()`, remove the rest
* Minor fixups
* Fixup Mac QL plugin install
* Fixup IDE target folders and source groups
This required some editing re. number of plural forms. Not exactly sure why
Kazakh still has one plural form there (contacted them for clarification).
Also, Manx (gv), Shan (shn), and Central Kurdish (ckb) languages aren't
supported by Transifex at the moment (contacted as well)...
Remove Belarusian (be@latin) as it was no longer present on Launchpad.
Add Welsh (cy).
