Adds export method

Switches to simpler interface for composite

Merge pull request davidbyttow#32 from davidbyttow/d/imagetype

Return final image type from Apply

Rearranges package layout to be more standard

Merge pull request davidbyttow#25 from Nafanya/feature/rotation

Add rotation operation

Fixes go vet

Adds a couple helper methods

Fixes error

Removes go-debug

Adds logging around image format