Synfig module: Add support for lossless AVI encoding. Requires Synfig 0.64.2 or later.
Use better approach for defining module parameters in project .conf file.

Syntax:
param_name=value        - Sets parameter value for all mdules having that option
module.param_name=value - Sets parameter value for particular module
Blender: Fix check for default value of CYCLES_SAMPLES
Belnder: Better check for incorrect values. In this case the incorrect value will fail before the file will be submitted as a job.
Implement "Extract alpha" option for Synfig module. Requires Synfig 0.64.2 or later.

Also, this commit implements smarter detection of source files.

For example:
* "/some/path/render/file.sif.png" unwrapped to "/some/path/file.sif"
* "/some/path/render/file.sif-alpha.avi" unwrapped to "/some/path/file.sif"
* "/some/path/render/file.sif.png/file.lst" unwrapped to "/some/path/file.sif"
* "/some/path/render/file.sif-alpha.png/file.lst" unwrapped to "/some/path/file.sif"
Fix a nasty bug which was triggering redundant renderings
Don't look for "extract_alpha" key if it is not defined