sync also to new community server
Refactor and expand sets/bags/mixes docs

The class docs now have their own .pod files in the Type/ folder (like all other classes).
The Sets_Bags_and_Mixes language page is renamed to setbagmix to fit in with the usual naming scheme.
All related .pod's are now also more fleshed out.
Fix issue #31
Merge pull request #32 from simula67/windows_doc_fix

Fix issue #31
Add a util for generating a stub doc for a new type
document Promise
[Promise] incorporate feedback from jnthn++ and lizmat++

* explain that you can only keep and break promises yourself if you created them with .new
* timeout example for Promise.anyof
[Promise] Make it clear that method vow returns a Vow
document class Channel
Channel: missing verb, jnthn++
Some text tweaks, hope moritz++ is ok with them