[LDCad] Rebrickable LDCad PBG export

[Vincent Messenet]

https://www.ldraw.org/hidden-content/pbg-test.html

More updates:
- I finally implemented the reason I wrote this generator: assembly replacement. Note that this is a manually created database. Currently it has about half of LDraw's minifg torsos (p codes 0 - a), control sticks (it was an easy test case), and unpattened hips and legs where the hips and leg colors are different (Rebrickable uses a pattern code scheme that allowed me to programmatically generate a list). This will expand out as I chug away at the list. The focus will be minifig/minidoll assemblies. If you have a category you want to see me implement sooner rather than later, let me know. The current, up-to-date list is located here:
https://www.ldraw.org/common/data/pbg_crossref.csv
- The de-pattern code is more robust
- The de-pattern checkbox actually works and is set to replace by default
- Fixed some other back end bugs.

Thanks Orion!

I just did a test with set 10272-1 and part 2339 is reported as not being official while it is: https://www.ldraw.org/parts/official-part-lookup.html?folder=parts&partid=2339

Otherwise, 3 patterns are replaced by default parts because their Ldraw references are wrong at Rebrickable:
10202p01: https://rebrickable.com/parts/10202pr000...ter-print/
10202p00: https://rebrickable.com/parts/10202pr000...ine-print/
90498p00: https://rebrickable.com/parts/90498pr000...rea-print/

Did you already submit a change request for these 3 parts?