Updating RapidPE/RIFT to v0.6.4, improving environment variable handling

RapidPE/RIFT 0.6.4 (and RapidPE 0.1.1) moves from hard-coding getenv = True in HTCondor submit files, to making getenv and environment completely configurable. Changes were also made to specify these variables, pass them to the config template, and pass them to condor_submit.

In addition to passing through existing envvars, we use environment to pass RIFT_LOWLATENCY = True, which causes RIFT to avoid unnecessary imports used only for offline runs to reduce latency.

We also fixed a bug in RapidPE/RIFT where search templates with m_2 > m_1 were being interpreted incorrectly, causing our prior range to differ from our expectation, and now we enforce m_1 \geq m_2.