[bindings] Implement bindings, solve name inconsistencies, fix #529

[bug] Fix sample geometry model and python geometry unit test

[unittest] Check that dIntegrate/dv * dDifference_dq1 = I

Version 2.0.0-alpha

Apparently, some older version of boost does not consider the comparison
between two variants. This should be fixed later.

When doing a git clone, travis use to limit the depth of the history,
which might lead to some problem with `git describe --tag` command.

This is due to the rebase between devel and release-2.0.0