Initial work on a homebrew-like system for performing self-constained, reproducable, and semi-automatic builds of external projects.
Fix a bug related to refactoring of metadata to be tradiational dictionaries instead of AttrDict instances
Merge branch '2.0'

Conflicts:
	python/rez/resources.py
Merge branch '2.0'
Merge branch '2.0'
-cosmetic change for testing purposes only.
Merge branch 'external_builds' of github.com:LumaPictures/rez into luma_ext_blds
-fixed (linux only) incorrect bash completion which was completing on non-pkg-version subdirs
-fixed bugs in build process wrt pkgs with no variant
-minor updates to pkg iteration
-fixed resolve bug in rez-help
-rez-help now uses webbrowser builtin module for better browser detection
oops, see previous commit msg
Remove now unused --wrapper option from rez-config
Fix a bug with tempdir cleanup: use shutil.rmtree instead of os.removedirs, since the latter only removed empty directories.
Make PkgConflictErrors more legible.
Add a test package with 2 dimensional variants.  Add tools to packages for future testing of wrappers.
-added basic templating API. This will probably be expanded in future
to use a more powerful templating engine such as Jinja. In particular
this will be used to make a pluggable rez-make-project.
-added platform_ submodule
-updated rex to use platform_
-changed references to 'os pkg' to 'platform pkg' to avoid confusion -
'os' now refers to distro, eg Ubuntu, osx.
-moved version number into more standard rez.__version__; install script
now reads from here.
Make sure that VersionRange('') intersects properly with ExactVersionSets
-some python2.5 compatibility
-moved platform_py to system.py, turned into singleton
-added shell detection to system.py
-improved on existing shell detection via psutil module, this is also x-platform
-added settings API
-removed some settings from configure/install.sh, now handled at runtime by settings singleton instead
-fixed rez-dot so you can change img format; changed default from jpg to png,
 jpg has issues on old centOS distros;
-added rezconfig file, part of new settings system
-ported Rex to use system.py
-removed some now unused settings from configure.sh
Merge branch 'nerdvegas/luma_ext_blds'

Conflicts:
	python/rez/config.py
	tests/test_config.py