Nmrespy

Major overhaul of NMR-EsPy, including support of analysing 2DJ data.

Esimator1D` now provides the `subband_estimate` method. This enables the entire signal to be estimated by iteratively performing estimation on frequency-filtered "sub-bands" of the signal.

write_result()` now features the `intergal_mode` kwarg, enabling integrals to be expressed relative to the lowest amplitude signal, or in absolute terms.

Fix from 1.1.2: included `MANIFEST.in` to ensure `images` directory is included in package.

* `get_result()` methods have been renamed `get_params()` for clarity.
* `make_fid()` now supports the `indirect_modulation` argument for phase- and
amplitude-modulated signal construction.
* Refactoring of estimator classes: various methods moved from `Estimator1D`
into the parent `Estimator` class as these behave in a general fashion.
* For result files with multiple regions, integrals are now comparable. Thanks
to Fay Probert for this suggestion.

Few bug fixes.