SVN takes a long time to sync even if there are no updates,
the `code_update` parameter gives the option opt out of the
SVN updates.
This is a developer option, people just wanting to build
blender and not do any development are highly recommended
to keep using the `update` method.
make.bat was starting to become hard to maintain, this refactors it into separate batch files for each stage of the process.
-Improved detection of msvc2013/2015
-Improved failure handling.
-Added check for working msbuild and C++ compiler
-Added verbose switch to ease trouble shooting.
-Added Check if svn/cmake/git are in the path before using them
-Display the build configuration before asking to download the libraries
-Offer an option to recover an interrupted checkout of the libraries.
-Automatically check out sub-modules in-case they are missing.
