New Push Button

-Touch event implementation of PushButton
Merge pull request #19 from maylencita/master

New Push Button
rename things for consistency
call f then g and avoid calling g multiple times
rename the PushButton object
add MousePushButton
must lock a PointerupButton when it's monotouchable
add PointerPushButton
fix readme
add the setG function to the various PushButton implementations
document the PushButton
bump version to 0.7.0
Merge pull request #20 from bapmrl/master

New PushButton
Merge branch 'master' into gh-pages
npm run build