Removed controller enum
Removed unnecessary controller related code that is not used at the moment
Removed dev related code
Added comments and enabling sending setpoints to the simple example
Enabled sending setpoints in the replugging example
Removed the (very messy) dev example from the master branch
Removed the (currently unused) DataStructures.h file
Fixed the `thrust()` function and added doxygen documentation
Extended the README.md file by an explaination of the `ex-gui` program