Fix small bug with dirty attributes and list assignment as an array.
Add spec to assert issue with dirty attributes

* When using a delimiter different from "," the dirty attributes
  should remain empty when assigning the topic list with an array:
Remove unnecessary dependencies
fix README: add parse:true documentation
seperate usage to several blocks
Requiring acts_as_taggable_on warns to require acts-as-taggable-on
Bump to 3.0.0.rc2
Bump to 3.0.0; update CHANGELOG
Correct README re: 3.x now released
Merge pull request #406 from rafael/master

[Fix]  dirty attributes incorrect when list assignment as an array and non-comma delimiter
fix strict_case_match bug
Merge pull request #440 from BenZhang/master

[Fix] Comparing tag names now respects strict_case_match
Merge pull request #386 from billychan/fix-readme

[Doc] README: add parse:true documentation
Refractored README.md and UPGRADING.md
Post install message fix
Merge pull request #449 from seuros/master

Improve migration/upgrade instructions
Remove I18n Deprecation warning in tests.
Add ruby 2.1.0 to Travis
Merge pull request #452 from seuros/master

[Tests] Remove I18n Deprecation warning in tests.
Merge pull request #453 from seuros/travis

[Test] Add ruby 2.1.0 to Travis