Native/Embedded UI integration tests

[vzahradnik]

Is your feature request related to a problem? Please describe.
Currently there is no way how to automate UI testing. The TcMenu library can be broken at any time and we are checking the rendering manually on real devices from time to time. It is very hard to avoid regressions when updating the library.

Describe the solution you'd like
We should come up with a testing framework which allows TcMenu to render the output into some dummy display and then we could compare the output with some known value to make sure nothing was broken. It will save us a lot of time going forward.