[MAILPOET-1822]
[MAILPOET-1791]
mb_detect_order
* Load mb_strtoupper() polyfill for MP2 migration * Add "symfony/polyfill-mbstring" as explicit dependency * Fixate AspectMock at 2.0.1 * Generate composer.lock with PHP 5.6 to include required dependencies [MAILPOET-1234]
- Adds polyfills for mb_string functions - Aborts initialization if PDO extension is not found (critical requirement)
