smart defaults for parameters

[fherwig]

Several of the parameters (see also related issue #2) can have smart defaults to be determined automatically. For example the
hdf5_codev = 'some/string/in/your/data' parameter
should contain by default a string like "mesa rev"+svn info --show-item revision which expands to "mesa rev 9331", for example.

The parameter hdf5_prefix = 'M3.00Z0.020' can be generated automatically from inlist parameters mass and metallicity given in inlist.

[jcpassy]

I opened a PR this feature (branch issue-3). Seems to work fine for me. Can you review/test it?

[jcpassy]

I think this is resolved on the develop branch. Can we close?