version updated
adds the possibility to sort by exercise-type
fixes crash, if attribute doesn't exists
belongs to #114
crash fixed, unknown $uid
adds submissions and markings only if "hideFile" flag is not set
(*) replaced with (B) for exercises with bonus flag
adds calls to remove file types by exercise-id  and sheet-id
corrected exercise order
adds options for direct calls of  instruction() and commands()
adds sql templates for calls to remove file types by exercise-id  and sheet-id
adds class to simplify component creation
reworked to use Model.php
no functionality
uses CacheManager
adds calls
table modified (default 0 for maxPoints)