Reverted sequence node style change
Improved layout of command list

Make better use of space and reduce visual clutter. Note command
comments take up full line and don’t have a button background.
Display error icon on right hand side of command
Fix #46 - commands now store reference to their parent sequence

The reference to the parent sequence is only populate at runtime, so
don’t try to use it in custom editors, etc.
Merge remote-tracking branch 'source/master' into develop

Conflicts:
	Assets/Fungus/FungusScript/Scripts/FungusScript.cs