Adding python bindings for fiber.QuadratureOptions
:bug: Wrong binding for TETRAHEDRAL topology
Add option to freeze QuadratureOptions

Freezing the options can only be done cython side. It is tested by creating a
small cython module in testing. As a result, the tests are now fully fledged
sub-packages of bempp.
Add wrappers for AccuracyOptions

The wrappers are almost a reimplementation of AccuracyOptionsEx. This is meant
to expose a bit more than straight c++ would allow.
Might be changed later on if inadequate or if snowballs.

Goes some way towards #129.
Start of an options class

This class is created via mako
Changes bempp target to libbempp

This is to accomodate a python bempp target.
Adding tests for aca options

This is the first complete python module with mako.
Python headers are now handled independently. This is necessary since the
cython source files depend on the generated cython header files. So all mako
generation should happen before cython is called.

In order for cython to find generated and normal pxd files, the headers are all
installed within the bempp package. This goes some way towards #139.

Also goes some way towards #128.
bempp.options.Options wraps instance of AcaOptions

Rather than redeclaring variables. This is simpler and makes back and forth
between python and C easier.
Test for AcaOptions python -> c unnecessary

Since now an AcaOptions is actually owned by bempp.options.Options
Add parallelization options
Added most of bempp options

Goes through mako options.
Still needs some few hand tailored options.
Unified previous options into a single dictionary that describes the wrapper
implementations.
Added some options. Cleaned up a bit.

Added assembly_mode.
Removed do_opencl since it seems to be disabled.
All options now defined via same 'options' dictionary, and sharing mako defs
where possible.
Added failure tests for initialization and options that take a finite set of
options.
Adding accuracy to general options

Modified RangeAccuracyOptions to have default arguments, in line with c++ code.
Add basis and result types
:bug: in tests from bempp->libbempp target change

Introduced in c125db1. Did not correct test projects then.
Remove unnecessary file
More explicit docstring for range_accuracy_options
Cython 0.19 does not allow dosctrings for variables in pxd files
Merge pull request #153 from bempp/rsdt/cython_context

Rsdt/cython context