Fixed warnings when compiling release.
Updated MurMur3 hash

Now always using the 32-bit versions of MurMur3 hashing. The 32-bit and
64-bit versions produce different hashes, which causes problems when
they're processed offline, so go for the lowest common denominator.
Updated the readme with a bit on licenses.
Updated version of premake4

Updated to one of the most recent releases for better support in C#
projects.
Always have CheckedHash functions available

The supporting functions behind CHECK_STRING_HASH_VALUES are now always
available. This removes the need to recompile the entire library to
enable the check on a per-file basis.
Added command line tools

This commit includes the basic setup for the command line interface to
tools and command line parsing, a MurMur3 implementation to be used by
the tools and the StringHasher commandlet to parse and hash string with
a specific tag around them in source code. (Defaults to STRING_HASH_32).