* new/project.jam (lookup): Bugfixes. (find-target): Attempt to load
project specified by project id.
Project module rules:
project: Allow empty id.
use-project: New rule.
* new/targets.jam: (basic-target.generate-source): Correct a bug in
separating target id from extra properties.
[SVN r14341]
* new/build-request.jam (expand-with-defaults): New rule
* new/build-system.jam, new/targets.jam: Use 'expand-with-defaults' instead
of 'expand'.
* new/builtin.jam: Define new feature 'threading'.
* test/project_test3.py: Test that feature defaults are applied.
[SVN r14307]
* new/targets.jam: Check for duplicate 'basic-target::generate()' calls.
Use better logic to tell is source is another main target or file.
(project-target::has-main-target): New rule.
* new/project.jam (lookup): Fixes. (find-target): Implemented.
* new/make.jam: New file, defines the 'make' rule and associated target
class.
* new/build-system.jam: Import 'make'. Generate virtual targets and
actualize them.
* new/utility.jam: Added "MkDir" rule and actions.
* test/project_test3.py: New test.
[SVN r14249]
