add isLabelVisible property
Remove automatic centerlabel setting
Remove unnecessary isLabelVisible set
Update README.md

add label usage example.
Remove unnecessary font setting
Rename property
Add centerLabelVisible to example
use NS_ENUM, add missing nonatomic
add isLabelVisible accessor
add shorter init, allow view to be resized
add ipad support
amend: add radius property
stop fractional pixels
update example to use short init
add tap to resize views
fixed conflicts, add short init info to README