Boost vagrant vm memory and add a processor

Building the node mapnik bindings takes an extremely long time unless you
give the VM some room to move.
Merge pull request #37 from jwalgran/topic/more-vagrant-vm-power

Boost vagrant vm memory and add a processor
Fix command chaining so umount actually runs
Modify VagrantFile and bootstrap.sh to work with vagrant 1.2+
Merge pull request #39 from azavea/topic/buildFixes

Topic/build fixes