Added dummy _reset_select() method to CI_DB_Driver class to allow Active Record class to be disabled. Otherwise a fatal error is triggered.
Changed form_open() to compare $action against base_url()

Checking for strpos($action, $CI->config->site_url()) === FALSE causes
CSRF token to not be added in form_open() output. When site_url()'s
first parameter ($uri) is empty, site_url's return value is the base
URL plus the $CI->config->item('index_page') value. form_open() and
CodeIgniter's URI routing do not require index.php to be in the URL, so
any call to form_open() in which the $action parameter does not have
index.php will always return false for the strpos() call.
Merge pull request #710 from johnnicely/2.1-stable

Changed form_open() to compare $action against base_url().
This fixes issue #725
Merge pull request #729 from Repox/2.1-stable

This fixes issue #725
Hotfix for a file type detection bug in the Upload library
Update a comment, just to be clearer
Update the change log
Merge pull request #733 from narfbg/2.1-stable-upload-hotfix

Hotfix for a bug in the Upload library
Improve CI_Upload::_file_mime_type()
Update the ChangeLog
Fix for Issue #538.
Fix regular expression for validating MIME type string
Updated changelog with fix for bug #538.
Tweak MIME regular expression check again
Merge pull request #766 from andrewmackrodt/2.1-stable

Fixed issue #538: CI_Image_lib->new_image doesn't recognise backslashes
Merge remote-tracking branch 'upstream/2.1-stable' into 2.1-stable
Merge pull request #709 from tubalmartin/2.1-stable

2.1.0 - Fatal error: Call to undefined method CI_DB_Driver::_reset_select()
Merge pull request #757 from narfbg/2.1-stable

Improve CI_Upload::_file_mime_type() realiability (2.1-stable)
compile binds before caching the query, otherwise the cached query will never match the unbound query. updated changlog to mention bug fix.