CMake: Do not add MimetypesQt4 sources when using Qt5
Copy cmake-2.8 script CMakeDependentOption.cmake to cmake/TrojitaOption.cmake
CMake: Update TrojitaOption.cmake

Add macros:
trojita_string_option - common string replacement for CMAKE_DEPENDENT_OPTION
trojita_option - AUTO/ON/OFF tristate replacement for CMAKE_DEPENDENT_OPTION
trojita_find_package - wrapper around find_package, set_package_properties and
                       handle AUTO state of some options
trojita_check_qt4_module - qt4 helper macro for handling AUTO state of options
Add cmake file FindMakeNSIS.cmake
CMake: Use macros from TrojitaOption
Travis: restore builds which test WITH_RAGEL=off

It looks like ragel is installed by default in Travis; let's make sure that we
build one configuration where it's explicitly disabled.
Merge branch 'pali-cmake'

REVIEW: 112766