fixed memory leaks
Merge pull request #8 from yyjim/fix_memory_leak

fixed memory leaks
use initWithCoder instead of awakeFromNib to allow customisation from IB
calculate corner radius from size of know otherwise it might be not circle
Merge pull request #10 from YPlan/feature/fix_corner_radius

Feature/fix corner radius
Merge remote-tracking branch 'origin1/master'

Conflicts:
	MBSwitch/MBSwitch.m