use NanNull, NanNew & NanSymbol for 0.11.11+ compat
remove unnecessary gitignore file
do not publish tests files
Replace use of deprecated libvips conv method.

Ensure unref of mask to fix minor memory leak of ~150 bytes/image.
Add warning about liborc memory leaks. #21
Add quality and compressionLevel options for output image. #24
Version bumps
make travis test on node 0.11
use master branch of image-magick-native until the 0.11 compatible is out
Merge branch '0.11-wip' of https://github.com/pierreinglebert/sharp into pierreinglebert-0.11-wip

Conflicts:
	package.json
Merge branch 'pierreinglebert-0.11-wip'
Remove liborc from CI config (to match README)