Currently working on the sharing of styles, + 6 bug fixes

Currently working on the sharing of styles.

Major fix: issue 87 (C4View doesn't receive touches when added from
Interface Builder)

Minor fixes: improved C4View / C4Window implementations (#88), checked
shadow implementation (#72), MVC (#71), self.canvas (#33), object.frame
|| object.bounds (#67)

for more check:
https://github.com/C4Framework/C4iOS/issues?page=1&sort=updated&state=cl
osed
Deleted C4CanvasView