Add tilt as dependency

Tilt is used as dependency in the injector, but is not included in the gemspec. This makes it impossible to launch the mockup serve without adding it in the local gem file, which sounds unwanted.
Merge pull request #14 from edwinvdgraaf/add-tilt

Add tilt as gem dependency
Update changelog
Correctly pass file and linenumber to Mockupfile evaluation
Release 0.6.1
Regenerated gemspec for version 0.6.1
Improve cleaner
Version 0.6.2
Regenerated gemspec for version 0.6.2
Add license to gemspec
Add empty directories to gem too
Add license to gemspec
Add option to extractor so you can specify which attributes to fix URL's in
Add command in mockup so you can pass extractor options
Make interfaces for finalizers and processors unified
Update Finalizers::Dir to new options interface
Whitespace & debug code removal
Fix adding custom finalizers
Fix error if node can't be found in Processors:Requirejs
Prepare for release