Added support for embedding qml resources into executables

[gemmarx]

It is ready to try in my fork repo.
This experimental hack has, however, been checked on an x86-64 linux box.
Would anyone help me to do more checks and support windows or mac osx etc.?

examples/factorial_qrc.rs gives an example of use.
After building of crate,

$ cd examples
$ make factorial_qrc
# or if you have built with --release option,
$ make BUILD_TYPE=release factorial_qrc
# An execution file will be made under /target .
$ ../target/debug/examples/factorial_qrc

Move the executable binary to anywhere you like, and it works stand-alone without qml files.

I can put this building process in build.rs for cargo, but I do not know how to switch conditions in the script with or without --example option.