Fixing problems with isOwner() in all backends
Correcting typo in FindFreeImage
Adding support for casting seq to array
Default constructor now creates array of size (0,0,0,0)
Merge pull request #256 from pavanky/iota

Fixes to af::array class
Added memory manager for pinned memory

* Allocates, resuses and destroys pinned memory
* Added dummy static class to call garbage collection at the end of the program
Using pinned memory in imageio
Changed API for iota

* Using -1 as rep to deal with no reps
* Simplified API
* Doesn't break existing API