VERSION file breaks vcflib build on Mac

[Adam Novak]

I'm trying to build vcflib for Mac. vcflib now includes this library as a dependency, and if it isn't installed it points the build process at a vendored copy in a submodule.

It adds the repository root of that submodule to the compiler's include search path, so you can #include <wavefront/wavefront_aligner.h> or whatever.

However, the repository root contains a file named VERSION, and on my Mac at least, line 37 of the C++ standard library header /Library/Developer/CommandLineTools/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/cstddef is:

#include <version>

Because Mac is case-insensitive, the WFA2-lib VERSION file ends up getting included by the standard library, instead of the standard library's version header file.

Please rename the VERSION file to something else (maybe VERSION.txt), or move the wavefront directory into another level of subdirectory (maybe include or src), so that vcflib can include from it without having this happen.

Alternately, vcflib could change its build process to install WFA2-lib into a directory somewhere and then build with it from there.

[Santiago Marco-Sola]

Thanks for PR, @adamnovak. Much appreciated.