Many changes:

+ New API for sequences parsing. It supports 3 kinds of operation:
1) Generate a pattern from a series of files.
2) Find all files matching a mattern.
3) Generate file names from a pattern and given arguments.

+ The sequence file dialog has moved to this API and is now more clever.

+ The sequence file dialog in SAVE mode is now more convenient and will
select automatically the file extension given the user selection.

+ The Nuke layout extension is now supported as it should be and
corresponds to the behaviour Nuke has.

+ Many bug fixes that prevented a project to be saved and rendered in a
separate process correctly.