BRANCH 4.1:
  added a general video icon file
  added m4v to the list of VIDEO_EXT
  skipped the files with NORMAL_EXT and VIDEO_EXT when running icon generation
  put try/except around the running of ffprobe
BRANCH 4.1:
  - added a SQL compliant way of stating a portion of where condition return empty result set.
  - filtered out timestamp as sqlserver_timestamp for SQLServerImpl
Merge branch '4.1' of https://github.com/Southpaw-TACTIC/TACTIC into 4.1