The run_on_start option doesn't currently work unless run_on_all is also set to true.
This fix decouples the two options so you can set them independently.
run_on_start option is no longer dependent on the run_on_all option.
fix (refix?) naming class between Guard::Rake class and module
I also fixed a name clashing issue which looks like it has reappeared.
Guard::Rake was defined as both a class and a module.