Simulate a complete custom exception handler by redirecting uncaught events.
Remove unnecessary chdir() in the shutdown handler.
Add changelog entry for #2633.
Make the changelog entry for #2633 more descriptive.
Merge pull request #2633 from kaiwangchen/simulate_complete_exception_handler

Simulate a complete custom exception handler by redirecting uncaught events
[ci skip] Simplify changelog message for PR #2633
Fixed issue #2638 which prevented loading models in sub-folders by passing an array.
Removed new line from the end of the file.
Drop the unused  parameter from log_message() / CI_Log::write_log()
Improvements to safe_mode detection (it doesn't exist in PHP 5.4)
Update MySQLi to use the PHP API for transactions, where possible
Merge pull request #2641 from aanbar/develop

Fixed issue #2638
Fix a PostgreSQL string escaping bug and use pg_escape_literal() when possible
Fix #2639
Fix array notation fields for set_select() as well