Merge pull request #87 from notohiro/master

add isOnMemory function to check wether an object is currently cached in memory

update readme for 2.3

update podspec for 3.0.1

add 3.0 title

bump version in podspec

Merge pull request #55 from Vkt0r/improvements

Improvements in the code

add swift 2 note to Readme

Merge pull request #23 from gilesvangruisen/master

Bump podspec version to 1.0.2

Merge pull request #6 from klaaspieter/swift-1.2

Swift 1.2 support

update demo project and Readme