Fix removing of parent project requirements

svn path=/trunk/tools/build/v2/; revision=64364
Use Property, not string, in more places

svn path=/trunk/tools/build/v2/; revision=64382
Make default build work.

Also, return non-zero status if there were errors.

svn path=/trunk/tools/build/v2/; revision=64384
More changes

svn path=/trunk/tools/build/v2/; revision=64406
Fix header dependencies processing.

svn path=/trunk/tools/build/v2/; revision=64407
More header dependencies fixes

svn path=/trunk/tools/build/v2/; revision=64408
Various fixes

svn path=/trunk/tools/build/v2/; revision=64426
Fix requesting specific files on the command line

svn path=/trunk/tools/build/v2/; revision=64427
Update virtual_target.py

svn path=/trunk/tools/build/v2/; revision=64428
Don't pass None for property set

svn path=/trunk/tools/build/v2/; revision=64429
Port notfile.py. Attempt to clean the mess with decorating action names.

svn path=/trunk/tools/build/v2/; revision=64431
Redo naming of actions again. Return values from Python to Jamfiles.

svn path=/trunk/tools/build/v2/; revision=64432
Fix expected status

svn path=/trunk/tools/build/v2/; revision=64433
Port cast

svn path=/trunk/tools/build/v2/; revision=64434
Fix project.find again

svn path=/trunk/tools/build/v2/; revision=64435
Add stub port of os.jam.

svn path=/trunk/tools/build/v2/; revision=64444
Update port of tools/types/lib.jam

svn path=/trunk/tools/build/v2/; revision=64457
Port tools/stage.jam.

svn path=/trunk/tools/build/v2/; revision=64458
Fix the 'chain' and 'inherited_dependency' tests.

svn path=/trunk/tools/build/v2/; revision=64460
Fix indirect conditional requirements.

svn path=/trunk/tools/build/v2/; revision=64461