clearItem() accepts a model instance

 On branch clearitem-entity
	modified:   backbone.fetch-cache.js
	modified:   spec/backbone.fetch-cache.spec.js
Fix syntax error in specs.

 On branch clearitem-entity
	modified:   spec/backbone.fetch-cache.spec.js
Minor update in README

 On branch clearitem-entity
	modified:   readme.md
Docs for new and improved clearItem()

 On branch clearitem-entity
	modified:   readme.md
Merge pull request #107 from madglory/clearitem-entity

.clearItem() with entities