auto-record user's actions as musescore commands as valid c++ code which can be easily copied as a mtest function

Basically record everything that the user does in musescore GUI as a series of libmscore commands written in valid c++ code, which could properly be executed as a mtest function. This is something that has been on my head for a while, and then when I saw that crash reporting is a possible GSoC 2017 project, I thought it might be great to do this as well, since getting a reproducible set of commands to produce a bug is one of the first steps to debugging. Also would be useful for creating test scripts.