tools: parse_rdesc: split more robust

The previous split (with ' ') failed if 2 spaces were one after the other.
tools: parse_rdesc: externalize get_human_descr() call

this allows to call get_human_descr() out of the dump_report function
tools: parse_hid: split dumping from translating

now we translate the event, and then we write it.
tools: parse_rdesc: re split out the parsing in a per event processing

the idea is to be able to get the partial output of the parser at each
value.
Tested against the HID db before and after the patch set
tools: add first gui for editing HID reports descriptors

still lacking a lot of features (save, save as, ...) but works
already quite well.