Feature/move jvm opts

Fixes setting the kernel parameter for Postgres shared memory, and moves the JVM options to the special file sbt looks for to find those.
Nice! These will be useful. Might want to pull it out into it's own object, since you've used it twice and probably will be good to use other places (`com.azavea.opentransit.Timer` or something). I did a couple methods like this in geotrellis-transit: https://github.com/geotrellis/geotrellis-transit/blob/master/src/main/scala/geotrellis/transit/Logger.scala#L38