Bumped version to 1.5.1
As a part of the task T50726:
Update the Panel rename code to more generic one

PEP8 cleanup:
Tuple imports and use them for class types
Consistent Scene props definitions
Update url link

Note:
Moved the Scene Properties into a PropertyGroup
Access them with bpy.context.scene.bsurfaces

There are still some possibly unused variables
In the future, during a refactor that could
be adressed (as they are not all function calls)

Fixed some crashes that i got during testing:
line 1402:
The Remove Doubles treshold calc in one case
caused divide by zero - fallback to 0.0001
line 458:
Index out of range error
line 2955:
zero Vector angles
If there are some better solutions, these are the
places to look