Grouping

Got grouping control "working." Currently:
- Can create groups and control all faders from Master Channel (channel
with highest progress value)
- Can dynamically add channel to a group
- Channels adjust relatively to Master, current maths is (master
progress - slave progress from group initialization) will have to do
some better maths to get more accurate positioning
- Current problems are but not limited to:
- channels not properly being removed from groups, causing sliders not
to be able to be updated once channels are removed
- need better math for relative positioning of sliders
- can only control sliders from master (can move slave sliders, but will
snap back once master is adjusted)

Will work on it more hopefully later tonight