Merge pull request #13 from Robinisabadguy/master

update setBackground
Merge pull request #14 from Robinisabadguy/master

merge scale and rotate
painting area zooming issue fixed
fix issue background image renew in new paint area
Merge pull request #15 from Robinisabadguy/master

fix hide keyboard issue
fix issue: frame misplace when zooming
Merge pull request #10 from kukushi/master

update