TPRParser does not support TPX version 112 from Gromacs 2018

[erlendurj]

MDAnalysis 0.17.0 fails to open .tpr files of Gromacs 2018. The minimal example I can think as an example results in the following error:

import MDAnalysis as MDA
u = MDA.Universe('ef0_nemd_base0028.tpr','ef0_nemd_base0028.trr')
Traceback (most recent call last):
File "", line 1, in
File "/usr/local/lib/python2.7/site-packages/MDAnalysis/core/universe.py", line 280, in init
"Error: {2}".format(self.filename, parser, err))
ValueError: Failed to construct topology from file ef0_nemd_base0028.tpr with parser <class 'MDAnalysis.topology.TPRParser.TPRParser'>.
Error: Your tpx version is 112, which this parser does not support, yet

[orbeckst]

TODO

• build Gromacs 2018 TPR (same system as the other TPRs)
• hack TPR parser
• write test

[jbarnoud]

I updated the tests, I'll fix the parser itself latter this week.

[jbarnoud]

Having the TPR parser pass the tests was surprisingly easy. Yet, the tests are based on older file that get converted. Would somebody have a TPR that use the latest features of gromacs 2018, it would save me some time. I'll generate some anyway, but I am using a very small subset of the features.

[jbarnoud]

Ready for review.