Add drag term and SU to swe model

- Added quadratic drag term in the Firedrake shallow water model.
- Updated SU stabilisation.

git-svn-id: svn+ssh://svn.ese.ic.ac.uk/svn/people/ctj10/firedrake@1144 991910df-fe59-4c73-bf9a-89806fd8247c
Add test Makefile and schema options

- Added a Makefile for the standing wave test case.
- Added options to the schema so the user can choose whether
  to integrate the continuity equation by parts.
- Users can now enter surface IDs for BCs in their .swml file.

git-svn-id: svn+ssh://svn.ese.ic.ac.uk/svn/people/ctj10/firedrake@1145 991910df-fe59-4c73-bf9a-89806fd8247c
Create README.md
Added debugging statements and set ksp_monitor to True.
Merge branch 'master' of github.com:firedrakeproject/firedrake-fluids
The sw_standing_wave test case now uses the same mesh and settings as Fluidity's version.
Renamed the sw_standing_wave test case to swe_standing_wave.
More renaming.
Renamed the mms_shallow_water_p2p1 test case to swe_mms_p2p1.
More renaming. Get the Makefile to clean up .pvd files. Also updated the error plotting script.
Renamed the sw_wave_speed_1d test case to swe_wave_speed_1d, and added a Makefile to set up and run the simulation.
Updated the simulation name in the .swml file.
Updated 'UnitInterval' to 'UnitIntervalMesh'.
Created a new class called ShallowWater that helps to modularise the shallow water model.
Added docstrings.
Use "FacetNormal(self.mesh.ufl_cell())" if backend=="firedrake", otherwise use "FacetNormal(self.mesh)".
Set up the mesh and function space objects inside the ShallowWater class.
Set the output_function's name to FreeSurfacePerturbationHeight.
Added a file called test_swe_mms_p2p1.py for buildbot testing purposes.
Call 'make' from the test file.