[mh] Tasmota_HTTP_item.pm

All
I've been working on the async mode with Tasmota devices (I have over 50 
of them) and have made the following changes to
Tasmota_HTTP_item.pm (attached -  search for GGB to find changes)

1) moved the output file for async calls to data/tasmota_http to stop 
the data directory getting clogged in large installations
2) changed many of the print_log statements to use the new format 
print_log(message,severity,source) and added a few I needed
    to debug my additions
3) added condition checks at start of set code to allow devices detected 
elsewhere to be marked inactive or unplugged
    unplugged is for devices temporarily unplugged e.g. Xmas tree lights
    active is used for devices found not to be working but ought to be OK
4) bug fix to change $self->send_cmnd($cmd) to $self->send_cmd($cmd)
5) added a "this_set_by" attribute so that the set_by attribute is 
preserved in async calls and not
    always set to "process item"
5) added a print log to the async process_check to print out the status 
in the event of a failure

Before i do a pull request, does anyone have any other additions?

Happy Christmas/Holidays
Giles