This allows us to get rid of the hideous MATRIX_PATH_PART_EQUALS macro,
and prevents inconsistent usage of strcmp() (for example, !strcmp() vs
strcmp() == 0).
StrEquals() also has sensible behavior for dealing with NULL strings (it
doesn't just segfault like strcmp()).
This is useful for having a TLS and a non-TLS version port, like Synapse.
I verified that the multiple-servers does in fact work as intended,
although the TLS server part is broken; I must be doing something
incorrectly with LibreSSL in setting up the server.
