[hotfix/ZF-11661] Zend_Validator_File_IsImage - added MS x-png
[hotfix/ZF-11661] Zend_Validator_File_IsImage
- added MS x-png

zf2timo/zend-validator,ezimuel/zend-validator,zendframework/zend-validator,weierophinney/zend-validator,akrabat/zend-validator,svycka/zend-validator,Maks3w/zend-validator