Cpymad

- don't ignore exceptions from ``clibmadx._get_node_index``
- fix node positions for auto-inserted DRIFTs
- fix node positions for unexpanded sequences
- add some methods for sequence expansion
- change ``libmadx.get_table_column_count()`` to return number of *selected*
columns for consistency
- fix bug in ``Madx._use()`` that caused ``Madx.twiss()`` and other functions
to reUSE the sequence and thus clear previously selected flags
- force linking against libptc (required on py35 if MAD-X is installed in
non-system location, since ``DT_RUNPATH`` is non-transitive and does not
resolve libptc as indirect dependency via the chain cpymad->libmadx->libptc)

- update to MAD-X 5.05.01

- build windows wheels with bdwgc 7.6.8 to mitigate problems on win10

Please see the comprehensive list of changes and backward incompatibilities
mentioned in the prereleases!

In addition:

- update to minrpc 0.0.7
- the windows wheels are built using MAD-X 5.04.01

- update to MAD-X 5.05.00
- implement Madx.chdir using the new CHDIR command. This improves readability
and repeatability of command histories.

- remove support for python 3.5
- fix TypeError in jupyter on windows 10 (110)
- fix output to go to jupyter notebook instead of terminal on linux in recent
versions of python and jupyter