Fixed bevel modifier script error when Blender non-English language i…

…s used and Translate New Data is enabled

Instead of creating a modifier then looking it up in the modifiers array
by name to set properties, now we new the modifier directly on the
object and use the return value to set desired properties instead.

Merge pull request a1studmuffin#3 from panzi/master

added GUI, use os.path.join and create release ZIP