Renaming NMSSMTools run script and reading from stdin

Hi Ben,

these two commits do what you proposed:

 1. The NMSSMTools run script is renamed to `softsusy_nmssmtools.x`

 2. The script reads from stdin and writes to stdout. The user now calls it like

    `$ ./softsusy_nmssmtools.x leshouches < slha-input-file`