#1 Check return codes everywhere

[Markus Elfring]

Some checks for return codes are missing.

Examples:
Would you like to add more error handling for return values from "fprintf" in functions like "cfg_write_file" and "open_datasource"?
http://extace.cvs.sourceforge.net/extace/extace/src/configfile.c?revision=1.3&view=markup
http://extace.cvs.sourceforge.net/extace/extace/src/input.c?revision=1.22&view=markup