Active Calls, Assigning Calls, Restructuring

Performed large amount of maintenance to source code and structure/name
of the project.  Created new packages to help organize source files and
edited other classes to facilitate modularization.

LL-14:  Created web service that allows the user to claim a call by
sending over the pcr id into a header.  Will be updated to accept
crew/ambulance data in order to accurately claim the call.  Currently
inserts arbitrary value in vehicle id number field and removes from
active call listing.

LL-13:  Updated the preview builder to utilizing a separate mapping
system to keep track of previews and allow for quicker access when
previews are requested.  Removed preview from listing upon it being
claimed by a crew.