Merge branch 'develop' of git://github.com/EllisLab/CodeIgniter into develop

Conflicts:
	system/core/Loader.php
	system/database/DB_query_builder.php
	system/database/drivers/cubrid/cubrid_driver.php
	system/database/drivers/mssql/mssql_driver.php
	system/database/drivers/mysql/mysql_driver.php
	system/database/drivers/mysqli/mysqli_driver.php
	system/database/drivers/oci8/oci8_driver.php
	system/database/drivers/odbc/odbc_driver.php
	system/database/drivers/pdo/pdo_driver.php
	system/database/drivers/postgre/postgre_driver.php
	system/database/drivers/sqlite/sqlite_driver.php
	user_guide_src/source/changelog.rst
	user_guide_src/source/database/query_builder.rst