-Add the class OString, which functions as a drop-in replacement for std::string but makes use of string interning so that OString comparison can be done using integer hashes instead of strcmp-style comparison.

git-svn-id: http://odamex.net/svn/root/trunk@4200 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Fix a linking issue due to the non-member functions in m_ostring.h not being inlined.
-The OString versions of swap and getline should be in the std namespace.

git-svn-id: http://odamex.net/svn/root/trunk@4203 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Change inclusions of the deprecated <string.h> to <cstring>.

git-svn-id: http://odamex.net/svn/root/trunk@4204 b0bcef46-2027-0410-bd56-ab726e9a1d04
Remove unused cmdlib function RegexMatch as it never worked properly anyways.

git-svn-id: http://odamex.net/svn/root/trunk@4205 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Separate the OString implementation from its interface.

git-svn-id: http://odamex.net/svn/root/trunk@4207 b0bcef46-2027-0410-bd56-ab726e9a1d04