Splitable Bahtinov Mask Generator

Update v2.1
-fixed issue with one piece mask. Some slicers (Cura for example) has problems with slicing such type of mask.

Update v2.0
- changed shape of lockers
- fixed some bugs with sizes
- added parameter to set central bar width

This design was made on base of magnificent Bahtinov Mask Generator by *Brent Burton*.

The original design located here: http://www.thingiverse.com/thing:160391

For thouse LA who's printer is not big enough to make full sized mask for big telesope.

So I've made some additional features to original design.

Now it can be splited on 4 parts. Plus I've added posibility to make outer and inner borders.