Use NSCache instead of a dictionary for the memory cache.
Keeping original image alpha info when decoding

This fixes issue #26 and #55, after the change introduced in commit c32f9c03f816dac58a8cac25d6189310272ca9c1
Merge pull request #194 from NachoSoto/patch-1

Keeping original image alpha info when decoding
Creating the CGBitmapContext with the right bytes per pixel and bitmap info depending on the original image.
This removes an error that was making CGBitmapContext return NULL with some images:
<Error>: CGBitmapContextCreate: unsupported parameter combination: 8 integer bits/component; 32 bits/pixel; 3-component color space; kCGImageAlphaLast; 400 bytes/row.
Merge pull request #195 from JaviSoto/bitmap-info-error

Creating the CGBitmapContext with the right bytes per pixel and bitmap info depending on the original image.
Switch to framework distribution
Add missing installation instruction about linker flag
Fix #200 crash on archived builds
Fixed Alpha chanel detection when decoding images.
Merge pull request #203 from Stigec/master

Fixed Alpha detection when decoding images.
Send downloader as part of notification.
Merge pull request #183 from gotosleep/502f74042f10aa3a34d95a5e3f3e9a6500471554

Use NSCache instead of a dictionary for the memory cache.
Add NSCache's cost argument
Fix example app
Change deployement target to 4.x as NSCache wasn't available in 3.0
Revert "Fixed Alpha chanel detection when decoding images."

This reverts commit e6ede1104cea39f2034ec5a1644e2d2082cc57bd.
Fixed Alpha chanel detection when decoding images.
Fix alpha handling in image decoder (fix #204)
Merge pull request #205 from triposo/send-downloader-with-notification

Send downloader as part of notification.
Add cancelAll method (fix #168)