alc and gex header fix

[mp-emrld]

Did some minor modifications, so that Aarhus Workbench can read the xyz-data and alc-file written with libaarhus.dump(...) Might be a bit ugly but is working. Feel free to change the coding to be more "pythonic" ;-).

Did the following modifications:

• all channel/gate related information in .alc file must end on Gate_Ch01_45 not Gate_Ch01_[44].
• the first gate channel must be numbered with 01 not 00 (like Gate_Ch01_01 instead of Gate_Ch01_[00]).
• The xyz file must only have 1 header line, when input to AarhusWorkbench, so data['model_info'] must be skipped and not written to file.

[redhog]

A bit sceptical to including 9999 verbatim as a NaN value... Isn't this specified in a header in many xyz files? Possibly better to filter in the dataframe rather than in parsing maybe?