Added runtime check for imageWithRenderingMode: to prevent crash in iOS 6

Signed-off-by: Jai Govindani <jai@monstermedia.co.th>
Merge pull request #607 from zodio/master

Added runtime check for imageWithRenderingMode: to prevent crash in iOS ...
Merge commit 'd4f3298a2352222ed815fc32c83a7e97fcb5498f' into on123master

# By Jai Govindani
# Via Eduardo Scoz (1) and Jai Govindani (1)
* commit 'd4f3298a2352222ed815fc32c83a7e97fcb5498f':
  Added runtime check for imageWithRenderingMode: to prevent crash in iOS 6