Blender Git Loki

Export multiple frames to separate files.

Frame 20 with mentioned filename `name` is exported to `name020.obj`
It should be modified to exclude cases when a single frame is being
exported to avoid overwriting what the user intended to name it.

Also a filter is added to include only OB_MESH type objects for export.

The limits on frames can be changed, the current limits are like this:
Let's say unknowingly, the user selects the maximum 1000 frames & every
file is 1 MB in size. That will quickly fill up 1 GB on the disk.
More frames add to this risk.