Merge pull request #111 from bhattigurjot/master

fixes open file bug
implements move for circle, ellipse and text
Merge pull request #112 from kamalpreetgrewal/master

implements move for circle, ellipse and text
implements redo for circle and ellipse
Merge pull request #115 from kamalpreetgrewal/master

implements redo for circle and ellipse
Zoom Limit
corrects undo redo for line
Merge pull request #117 from kamalpreetgrewal/master

corrects undo redo for line