prevents complining the same source twice with the same properties.
Also allow generators to change source names using patterns.
* new/generators.jam (generator): Accept name patterns together with
target types.
(generator.generated-targets): Use name patterns. Transform generated
targets with 'virtual-targets.register', to eliminate duplicate
virtual targets.
[SVN r15302]
* new/sequence.jam (max-element): New rule.
(select-highest-ranked): New rule.
* new/numers.jam (__test__): Temporary disable all try/catch, since
errors.jam can't handle recursive try/catch yet, and loads
sequence, which in turns load numbers, in "catch" implementation.
[SVN r14922]
* new/targets.jam (make-target-alternative): New rule, which handles
applying project requirements and default build, when needed.
* new/make.jam (make): Use the above rule.
[SVN r14894]
* new/targets.jam: Use 'common' instead of 'utility'.
* test/project_test3.py: Test that 'clean' works.
* test/svn_tree.py: Sync with upstream revision 2944. Fix a bug
which caused empty directory to be treated as file.
[SVN r14886]
* new/modules.jam (import) Use the directory of the calling module
as additional search path element.
* examples-v2/make/project-root.jam: Remove workaround.
[SVN r14879]
* boost_build_v2.html: Extend feature description. Change wordings in
some places.
* new/feature.jam: Remove comments that are now in boost_build_v2.html.
[SVN r14782]
* test/TestCmd.py (TestCmd.cleanup): Print the names of preserved
directories. Reset self._dirlist even if directories are preserved.
* test/BoostBuild.py (Tester.cleanup): New method.
[SVN r14489]
* new/targets.jam (main-target.generate) Add extra path component to
virtual target which free properties are not equal to project's.
(basic-target.generate): Pass refined properties to 'construct'.
(virtual-target.extra-path): New rule.
(virtual-target.actualize): Make use of extra path.
* new/property.jam (take-free): New rule.
[SVN r14396]
* new/target.jam (main-target.generate): Give a more detailed error
message when no alternative is found. (basic-target.generate):
Don't exit with error when requirements can't be satisfied. Just
return an error string.
[SVN r14393]
