No longer saves the emcee sampler itself to the pickle. This was done in
response to a bug encountered by David Keitel in which while dumping the
pickle an error was raised. Fixes #1

Requirement is matplotlib>=1.4 in order to use the style package. Make the
default context ggplot (available in 1.4) and add an error message to
help the user when they have selected one which does not exist.

Makes this an optional module, adds it to the requirements and README.md

Adds proper unit support by default, and options ot customise through
the dictionaries

A hack fix for the internal error in LALSUITE - this should be reversed
once we have solved the fundamental issue: if the data contains no sfts
for that period, return 0 not nan

- Adds latex prior table writer (not found to be useful)
- Add special case of 0 to texify_float
- Expose texify_float in core
- Fix confusing argument order in GridSearch

If SFTs where not loaded, i.e. if injectSources was used, no timestamps
are generated. In such a case don't attempt to used them.

- Fixes undefined theta_values -> theta (missed as Ng > 1 isn't tested)
- Import from core rathern than explicitly
- Various PEP8 fixes

If nsegs > 1, a semi-coherent search is performed.

- Adds debug information
- If no data is in a given segment, a nan will be produced. Rather than
  summing this, the code will now replace it with zero and spit out a
  debug message to the effect.

As far as I can tell this should not be here (transient=True) in this
case. Nevertheless, I'm leaving it commented as this is quite a core
routine and I wish to remind myself to investigate it further.