Updating XSS cleaning to better handle base64 encoded attributes.

Conflicts:
	system/core/Security.php
Bumping version number to 2.1.2.
Fix issue #1543
Backport CI_Config::load() optimization from pull #1571
Alter CI_DB_pdo_result::num_rows()
Backport fix for issue #1314
Change is_loaded() to return a reference
Fix warning by profiler when userdata has objects

If session data has objects and profiler is enabled, a warning is trown:

> A PHP Error was encountered
> Severity: Warning
> Message: htmlspecialchars() expects parameter 1 to be string, object given
> Filename: libraries/Profiler.php
> Line Number: 514
Merge pull request #1675 from Dentxinho/patch-1

Fix warning by profiler when userdata has objects
Style fix and changelog entry for pull #1675
Backport a fix for oci8_result::num_rows()
Backport fix for issue #1699
Fix issues #227 and #907
Backport security fixes
Bump version number to 2.1.3
Fix issue #1715
Really fix #1715
Correcting the breadcrumb in the 2.1.3 update instructions.
Fix language typo in Migrations library

lang and line were out of order
Merge pull request #1936 from etcgroup/2.1-stable

Bug in 2.1-stable - language typo in Migrations library