[Qt-creator] Refactoring the CMake plugin

[Stephen Kelly]

Lorenz Haas wrote:

> P.s.: Another issue is how to have an equivalent for OTHER_FILES in
> CMake based projects. Currently I use "add_custom_target(Foo ALL SOURCES
> myfile.txt)". Good, bad, other suggestions? If there is a good
> "official" way of doing that, we should add that to the documentation.

 add_executable(main main.cpp myfile.txt)