Add option to exclude the examples.
Merge branch 'no-examples' into dev
checkpoint
undo parts of last commit
Add --jom and --jobs options.

--jom will use jom instead of nmake for msvc builds
--jobs will set the number of build jobs (-jN passed to make or jom)
Merge branch 'add-new-options' into dev
Fix path updates to not store the lower() version of the original path values.
Oops, we need to actually use OPTION_JOBS too.
Various additional build fixes and tweaks.

- Validate py_prefix and py_include_dir
- Add install_dir/bin to the PATH
- Set CMAKE_PREFIX_PATH to install_dir
- If QTDIR is set then use it for ALTERNATIVE_QT_INCLUDE_DIR
Merge branch 'more-build-tweaks' into dev
Merge branch 'add-new-options' into dev