Fix issue where D01 and D03 are implicit.

[rdprescott]

add the cappability to insert CommentStmt to debug primitive detection
fix issue where D01 and D03 are implicit

[coveralls]

Coverage decreased (-0.1%) to 88.9% when pulling 63a2ae2 on rdprescott:master into 45372cf on curtacircuitos:master.

[hamiltonkibbe]

Where does outlinecome from in the CamFile.bounds calculation in fa6cc86. That seems to be the only change that breaks the tests.

CamFile should really only ever used as a base class. The bounds method should be overridden everywhere it is subclassed (currently GerberFile and ExcellonFile). I don't see any reason to have an implementation in CamFile except to maybe raise NotImplementedError.

I'll take a look through the rest when I have a bit more time, Thanks for the contribution!

[phsilva]

I've started to get code from this PR to fix individual issues (like implicit D01 and D03). Would be good to try to rebase this PR with latest HEAD to see if it possible to split it more than one PR.