buildrequest collapse
 - TODO:
   - update master/docs/manual/customization.rst
break the brdict loop as soon as possible
 - do not use brdict term
 - use worst_status
 - don't ignore buildset with claimed br
 - Fix pyflakes
 - data.updates.completeBuildRequests have now the responsability of completing the parent buildset
move support for description{,Done,Suffix} entirely to BuildStep

Fixes #2949.
ForceScheduler: Fix issue when creating a 'simple' CodebaseParameter

In case we give strings to the parameters (to get fixed parameters), those should be converted as such.
Don't give value= in constructor of a ForceScheduler Parameter

We should use default=.
remove now-bogus tests for handling of description* args
Merge pull request #1271 from djmitche/bug2949

move support for description{,Done,Suffix} entirely to BuildStep

See ticket:2818
Fixes ticket:2949
Add test
Add test for #1277
Fix typo ...
Please PEP-8
Made MSBuild step's platform variable renderable
Removed unnecessary semi-colon.

Because after years of using them, you forget sometimes...
Merge pull request #1282 from benallard/patch-1

Add test for GH-1277
Merge pull request #1261 from delanne/buildrequestcollapse

buildrequest collapse
Merge pull request #1283 from Tsubashi/master

Made MSBuild step's platform variable renderable

Fixes ticket:2958
Merge benallard/buildbot:patch-2 (PR #1278)