Add the "TSFREQ" calculation type

[RaphaelRobidas]

Is your improvement related to a problem? Please describe. Some types of calculations can be combined in the same input file. For example, while it is possible to perform a geometrical optimisation (OPT) and a frequency calculation (FREQ) individually, ccinput also supports the "OPTFREQ" calculation type, which adds both the OPT and FREQ instructions to the input file. This could also be done for the TS and FREQ calculations, although it is currently not implemented in ccinput.

Describe the solution or change you'd like This calculation type could be implemented rather easily by reusing the code which handles TS and FREQ. One can refer to the implementation of OPTFREQ for a very similar solution.

A couple unit tests would be necessary for this new calculation type as well.