in cppcheck job, actually run make codecheck

maketools/cppcheck has been renamed into maketools/codecheck

To use it:
make cppcheck only runs cppcheck
make plumedcheck only runs plumedcheck
make codecheck runs both and aggregate messages (to be used e.g. on travis)

I added a awk script src/maketools/plumedcheck
that works similarly to cppcheck. It takes as argument
a list of files and analyze them.

[makedoc]

gaussian with grids, the check for sigma_min and
grid was not working properly

regtest reset

[makedoc]

[makedoc]

[makedoc]

[makedoc]

gromacs syntax (gmx_mpi mdrun) instead of (mdrun_mpi)

[makedoc]

[makedoc]

[makedoc]

[makedoc]

the gaussian support was wrong

- RESTART
- UPDATE_FROM
- UPDATE_UNTIL

[makedoc]