Fpylll

This is a bugfix release. Changes in fpylll-0.5.2dev compared to fpylll-0.5.1dev:

- `PKG_CONFIG_PATH` is derived from `CONDA_PREFIX` and `VIRTUAL_ENV` if available (Martin R. Albrecht)
- strategies take arbitrary auxilary attributes now (Martin R. Albrecht)
- enumeration for all data types - fixes 172 (Martin R. Albrecht)
- refresh cocal link (Frédéric Chapoton)
- documentation fixes (Fernando Virdia)

This is a bugfix release. Changes in fpylll-0.5.1dev compared to fpylll-0.5.0dev:

- [load_strategies_json broken in Sage](https://github.com/fplll/fpylll/issues/159) fixed in FPLLL
- [test_lll_lll fails on 32-bit platforms](https://github.com/fplll/fpylll/issues/160)
- [Flaky test in test_pruner.py](https://github.com/fplll/fpylll/issues/161) fixed in FPLLL

Major changes:

- Support for sub-solutions https://github.com/fplll/fpylll/pull/95 by Martin Albrecht
- Generate more statistics https://github.com/fplll/fpylll/pull/94 by Martin Albrecht
- avoid all LLL calls in postprocessing https://github.com/fplll/fpylll/commit/99bf78cfa288b286bbb9b78f3d4c7ae7bcafc988 by Martin Albrecht
- IntegerMatrix etc over longs https://github.com/fplll/fpylll/pull/77 by Martin Albrecht
- add GaussSieve https://github.com/fplll/fpylll/commit/66f825cfe010e7284535449385dd391bce2a4d56 by Martin R. Albrecht
- Support ReadTheDocs https://github.com/fplll/fpylll/pull/69 by Jeroen Demeyer