Add task to handle method renames.

Fixes #5
Fixes #6
Integrate rename method into upgrade shell.
Update doc block.
Update replacements to be less ambiguous.
Merge branch 'master' into method-rename-task
Update patterns so helper related patterns are separate.
Check for /View and /Template when choosing patterns.
Merge pull request #8 from cakephp/method-rename-task

Method rename task