nrwt: restructure manager code
Created attachment 147940 [details] Patch
Created attachment 149668 [details] roll-up patch based of of r121304 + mwb_cleanup + tw_cleanup Definitely not for review ... this patch needs a little more work plus all the tests revamped, then broken into more reviewable chunks, of course.
I don't think this technically relies on 76022, but it makes my git branching easier to think that it does ...
Okay, I've done most of the remaining work for this, so more patches will be showing up shortly ...
All patches have been landed (hopefully they'll stick). manager.py is almost a thousand lines smaller compared to the version in r122384 (the last version before I started moving stuff): 1582 lines -> 619 :).