Changed Commands module to RailsCommands.

This is to avoid a conflict that occurs when you add Rake to
your Gemfile. There is a Commands Object in Rake that conflicts
with the Commands module in plugin.rb. See rails issue #1866.
Substituted RailsCommands for Rails::Commands
MySQL2 Bump to 0.2.13
Merge pull request #2744 from arunagw/mysql2_bump

Mysql2 bump
use String#start_with? rather than creating regexps or comparing character values
* Psych errors with poor yaml formatting are proxied. Fixes #2645, #2731
* is not allowed in windows file names. Closes #2574 #2847
fix assert_select_email to work on non-multipart emails as well as converting the Mail::Body to a string to prevent errors.
assert_select_email entry
fix exists? to return false if passed nil (which may come from a missing URL param)
entry for fixing exists?
Merge pull request #2919 from akaspick/exists_fix_3_0

fix exists? to return false if passed nil (backport to 3-0-stable)
more descriptive CHANGELOG entry
Merge pull request #2918 from akaspick/assert_select_email_fix_3_0

assert_select_email fix for 3-0-stable
Do not use default_scope in ActiveRecord::Persistence#touch.
This way asserting that updated_at was changed in touch look more obvious.
Update changelog for 'Backport "ActiveRecord::Persistence#touch should not use default_scope" (pull request #1519)'
when calling url_for with a hash, additional (likely unwanted) values (such as :host) would be returned in the hash... calling #dup on the hash prevents this
fix url_for to not add additional unwanted options when called with a hash
Merge pull request #2939 from akaspick/url_for_fix_3_0

fix url_for when passing a hash to prevent unwanted additional values being added to the hash (backport to 3-0-stable)