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:
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
Fixed README
Fixed README
Added db:migrate
Renamed UPGRADING TO UPGRADING.md
Fixed typo
Merge remote-tracking branch 'origin/master'