PDF Charts + Print Queue

Squashed from the following commits

commit b8394a966f3067fcc02a8f213c7f752abb04fb07
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Mon Mar 24 16:54:35 2014 -0400

    Remove outdated printer update

commit 2867aa651b7390b9fc59f0d0fa80eb0ed5f20e8d
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Mon Mar 24 16:54:14 2014 -0400

    Add configuration option for redis host and port

commit 0663c50a5a4bd1f4147c2f53ddfdca635bb36a5b
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Tue Mar 18 14:21:00 2014 -0400

    Remove dependency on redis from tests + make them :green_heart:

commit 8fc0ca171854bca48be8a3c5ba053855092d4fc3
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Tue Mar 18 11:02:46 2014 -0400

    Font awesome, fallback to old print method

commit 69bc374994eb01b359961bca1f1dd091a76b1176
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Fri Mar 14 16:36:21 2014 -0400

    Check-in printer selection

commit 00e819e216e7ef26422e22c46c4886f5eaecc6bd
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Fri Mar 14 16:15:48 2014 -0400

    Don't clear all session data after logout

commit 53b3ba9d996db2e8f3b09c73bb8487fd2a398487
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Fri Mar 14 15:47:38 2014 -0400

    Add tests for PatientChart

commit 5db154e27a95210dfbb8259ce50018bfe5aa53dc
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Tue Mar 11 12:28:00 2014 -0400

    Background printing for patient charts

commit 95b9730ac6ba7b1241b10159c53f5031834c61cf
Author: Gregory Brown <gregory.t.brown@gmail.com>
Date:   Wed Feb 26 15:38:17 2014 -0500

    Use a proxy rather than a subclass to wrap Prawn's methods

commit 9a22630d1777ef69c6d771175a121b16ca30493c
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Sun Feb 23 14:51:01 2014 -0500

    Restore tests after pdf-izing patient charts

commit 1efa4548ca68a6050faa0bb484859d58d646e8c2
Author: Jordan Byron <jordan.byron@gmail.com>
Date:   Sun Feb 23 13:49:16 2014 -0500

    Generate patient charts with prawn for great justice