Setting `-DENABLE_UTILS=0 -DENABLE_TESTS=1` causes CMake errors due to
tests/utils/CMakeLists.txt referencing
`$<TARGET_FILE:transmission-show>` which is undefined. Fixed by
including the tests/utils/ directory only if `ENABLE_UTILS` is true.
* 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
