Fix User Guide Search button issue

Signed-off-by: Hashem Qolami <hashem@qolami.com>
Update user_agents.php

Added Win 8.1 user agent to the array
Issue #2763 - Fixes Session GC Probability Calculation

This should resolve issue #2763 where the cookie session garbage
collection was running every request.
Merge pull request #2764 from refringe/feature/cookie_session

Issue #2763 - Fixes Session GC Probability Calculation
Added post-increment for $count

It has been added the missing post-increment for variable $count.
DB call_function() bug : funny typo -or- smart autocomplete?
Merge pull request #2770 from kakysha/themostawesomebranchevercreatedforcodeigniter

DB call_function() bug : funny typo -or- smart autocomplete?
Fix #2775 (security lib docs)
Cleanup DB_forge _process_indexes
Cleanup DB_forge _process_indexes
Merge pull request #2777 from mjnaderi/develop

Cleanup DB_forge _process_indexes
Use table name as a prefix for index names
Merge pull request #2779 from mjnaderi/develop

Use table name as a prefix for index names
[ci skip] Add notes to get_compiled_insert(), get_compiled_update() docs
[ci skip] Fix a changelog message
EXISTS / NOT EXISTS clause support for  DB_query_builder.
EXISTS / NOT EXISTS clause support for  DB_driver
EXISTS / NOT EXISTS clause support for  DB_driver
changed EXISTS / NOT EXISTS pattern
@narfbg "It has parenthesis, so use the IN / NOT IN pattern as a base."
added changelog about EXISTS / NOT EXISTS
@narfbg "And you should also add a changelog entry for this addition. :)"