Miscellaneous bugs

[vsmagalhaes]

• holog fails when trying to overwrite a file (at least on lustre).
• holog_obs_dict is passed as reference in extract_holog when given, which may lead to the passed object being modified.
• image compare tool is picking full path for saving products when it should only pick filename
• core/extract_pointing sometimes raises a warning at line 393 about scalar divide
• It appears that the AIPS color scale might be different between the bar and the data (Test it with integer images).