The `execute` command now returns the output of the command instead of
printint it. This allows the tests to actually test the output of the
commands instead manually verifying that it is correct. It also allows the
library part to be used as an actual library that only returns data.
The tests are now sorted by command type. This allows for more consistent
test creation as tests can be done per source code file instead of per
object type.
Added helper functions for common testing operations. The two main ones
are doCommand, which executes a MaxCtrl command and returns a result, and
verifyCommand, that executes a command and verifies the result via the
REST API.