Update SIDSTARS for Baltimore/Washington (KBWI)

AVSIM FS2004-Flight Plans or NavData libraries. This is a major update to the KBWI procedures that have been included in my collections, which includes arrival and departure routing for use in lieu of ATC vectors. I've also added the non-published arrival from MXE VOR (MXE V378 BAL) that seems to be used by all arrivals from the Northeast. All FAA Preferred Route departures are included, since the only two published DPs are for Northeast-bound flights (the government has got to have an interesting reason for only publishing departures to the NE and only publishing arrivals from all other directions). Anyway, the KBAL update completes my effort of weeks providing procedures for the Washington DC area (KIAD already has over 300 downloads, KDCA & KBAL). Any real controllers or experienced VATSIMers are invited to critique my routing, I've designed them based on as much info as I could gather from flightaware.