Crash importing ALE from Colorfront into Clips bin

[dave (David McClure)]

This is fixed in v1.5.3 b5300.

@dave

FEATURES
GENERAL: In ALE import, use Filepath column for source filename if present (eg in Colorfront ALEs)
…
BUG FIXES
GENERAL: Fix issue where crash could occur if ALE is imported to clips bin with no image or audio file name