added basic tagging system
changes to MKtlElementGUI implementation

to make it easier to implement keyboard and pad combined views in the
future
fix MKtlElementArrayGUI for mixed types
change label of 'verbose' button to 'trace'
implemented elementsForTag. This closes #99.
implement combined pad on/off views

description files need to contain dicts with \on and \off keys for the
pads
Added ```printOn``` message. This closes #122.
make ElementGroups auto attach/detach

whenever an action is assigned
added name to printOn
updated to conform to current noteOn/noteOff description format
working on helpfiles
correct group adding

don’t add if already a parent
rearranging methods
Merge branch 'master' into refactorMKtlNew