Merge pull request #9 from t93/master

Bugfix: cannot turn off jpegoptim by `options.jpegoptim.use`
release: 0.9.11
fix contributor url
Fix: enable to change base ratio
Merge pull request #10 from CyberAgent/fix-ratioresize

Fix: enable to change base ratio
Update: docs
release: 0.9.12
Add: enable to select sprite builder
Merge pull request #11 from CyberAgent/sprite-builder-select

Add: enable to select sprite builder
release: v0.9.13
release: v0.9.14
Fix: ratioResize separator is undefined
release: v0.9.15
Fix: Require check of sprite library
Merge branch 'master' of github.com:CyberAgent/beezlib
Add: Limit on the maximum number of processes of image compression command
release: 0.9.16
Fix: sprite options is not passed
Merge pull request #12 from CyberAgent/fix-sprite-options

Fix: sprite options is not passed
release: v0.9.17