Various restructure of test framework handling of paths to avoid duplicate path editing which caused failed tests. Adjust many tests to deal with added subdirectories in build outputs now that toolset requirements are active.
* build/targets.jam
(project-target.find): Better error reporting.
* build/project.jam
(load-jamfile): Use 'path.native' when loading Jamfile,
otherwise, target id with absolute directory name won't
work for Windows.
[SVN r26271]
* new/virtual-target.jam
(from-file): Pass target name via "path.make".
(abstract-file-target.actual-name): Pass target name via "path.native".
* test/absolute_sources.py: New test.
[SVN r18324]
