Prevent division by zero.

See
https://github.com/stomita/ios-imagefile-megapixel/commit/5b2252cc14d412
24682f06c098c1b44fef0258d5
Use the faster bitwise operator instead of Math.floor and parseInt.

See
https://github.com/stomita/ios-imagefile-megapixel/commit/a8a96e47bb25c6
ad59f84a9144a38198ce974cfc
and http://jsperf.com/math-floor-vs-math-round-vs-parseint/33
Update demo jQuery version to 1.9.1.
Fixed image resize algorithm for subsampled JPEGs.

Thanks to Claudio (bytepan) for his patch to the original
ios-imagefile-megapixel library:
https://github.com/bytepan/ios-imagefile-megapixel/commit/f58d6d65c828dd
5741edf30d561220b3de94c42e
Create minified script and update package version.