Don't add empty tag if not tags have been specified.

Reported by Brant Anderson (by email)

The Atomic Blender panel is loaded correctly when a blend file is loaded.

Blendphys.

baking and render options for tags on slaves (default true for both means a slave can do all jobs by default)

from Alexander Gessler (aramis_acg) 

invalid operator return value when downloading results from a job with no finished frames

render jobs tags weren't set at all.

Reported by Brant Anderson (by email)

No commit message

Fix a typo "Confgiguration" -> "Configuration" 

Patch by Tobias Kummer (tobkum), thanks! 

Faces should be exported with shared vertices whenever possible (otherwise this is simply a STL exporter). Since PLY stores normals per vertex it's understandable that we need 'individual' faces when exporting normals. However when this is not the case I think shared vertices should be default behaviour. This is what this patch implement.

Thanks Campbell for reviewing it. Thanks Aldo Zang for reporting it (off trackers, in the old fashion real life)

Replace usage of mesh.faces with mesh.polygons

- pep8 edits for after effects script.

I'm working on fixing it, but that won't be in time for next release. Therefore I'm moving it to contrib until I'm done fixing it.

[[Split portion of a mixed commit.]]