ported 766c8861cb9280585dae60515ef8649706a203fb:
- handle malformed paths in AgaviArrayPathDefinition by throwing an exception
- update all relevant parts which use AgaviArrayPathDefinition and handle the exception if needed
- adjust tests 
closes #973
ported 47e373db28c9f58a5d4192e271a87142fdea6c2b:
fixed typo in 766c8861cb9280585dae60515ef8649706a203fb, refs #973