This matches the change that was done to the bevel modifier so that the
interface for the modifier, the active tool, and the operator are consistent.
This commit extends the refactor to the bmesh implementation too, so
that the parameters in the implementation don't stray too far from what
is exposed.
Tests are adjusted and still pass.
Blender was not configured to exit with non-zero return code on Python errors.
A bunch of tests worked around this but not all. This removes the need for such
workarounds.
Patch from Habib Gahbiche (zazizizou) moves the "run operator and
compare mesh to a golden" paradigm used in bevel and boolean tests
into a general framework that separates the test specs from the
blend files. Then adds some other operator and modifier tests using
the new framework. Diff D5357.id20724.diff was applied.
New .blend files, modifiers.blend and operators.blend are needed
in the tests/modeling svn directory; those were separately committed.
