1.2

Release 1.2

This is the last SOM release compatible with TRIQS 1.4.x.

- Improvements and small fixes in documentation.
- Added a new histogram post-processing function, `count_good_solutions()`.
- Fixed a bug in `update_glue_shift` elementary update.
- New benchmark `all_kernels` and fixes in the `chi` benchmark.
- Added Travis CI config for continuous testing and documentation deployment.
- Minor code improvements.