Only remove annotations with empty graphics when default extent present

Kind of covers part of #12
#12 Include rules for rotation, visible, origin, initialScale

I'm not really that pleased with the duplication of code in
order to catch the last occurrences. It is probably slowing down
things this way but I can't currently think of a better way.
Improves comment.
This is now the 0.5-dev version
Fixes the Dymola specific removals again
Refactoring (only whites spaces and naming)
Fix imports
Fiy typos
Merge pull request #14 from tbeu/t12-remove-defaults

Fix imports and typos
Hardcoding the "script_name" for now

For some reason it only returned `[]` earlier. So hardcoding for now.
Preparing the v0.5.0 release.
And back to development mode.