Work in Progress: Python 3 support.

[dadosch]

currently it fails, because with Python3 the way strings and bytes are handelt changed:

(maybe this is an issue with py-leveldb?)

2019-09-17 22:40:59,129 INFO pyGI.geigerlog: Fetching None log entries from 1568752859 to 1568756459
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/bottle.py", line 862, in _handle
    return route.call(**args)
  File "/usr/lib/python3/dist-packages/bottle.py", line 1740, in wrapper
    rv = callback(*a, **ka)
  File "/home/pi/PiGI/software/pyGI/geigerserver.py", line 59, in handle_ws
    client.receive_commands(clients_handler)
  File "/home/pi/PiGI/software/pyGI/geigerclient.py", line 66, in receive_commands
    handler.send_log(self,age=age_seconds,amount=None)
  File "/home/pi/PiGI/software/pyGI/geigerclient.py", line 152, in send_log
    history = self.geigerlog.get_log_entries(start=start,end=end,age=age,amount=amount)
  File "/home/pi/PiGI/software/pyGI/geigerlog.py", line 187, in get_log_entries
    return self.get_log_entries_all(start,end)
  File "/home/pi/PiGI/software/pyGI/geigerlog.py", line 115, in get_log_entries_all
    entries_list = list(self.db.RangeIter(key_from=str(start),fill_cache=True))
TypeError: a bytes-like object is required, not 'str'

[chron0]

not sure, haven't run it on 3 yet, so no shareable prior porting experience to offer :/

[dadosch]

This commit makes the webui work, everythings seems to work fine, except saving the configuration

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/bottle.py", line 862, in _handle
    return route.call(**args)
  File "/usr/lib/python3/dist-packages/bottle.py", line 1740, in wrapper
    rv = callback(*a, **ka)
  File "/home/pi/PiGI/software/pyGI/geigerserver.py", line 59, in handle_ws
    client.receive_commands(clients_handler)
  File "/home/pi/PiGI/software/pyGI/geigerclient.py", line 107, in receive_commands
    cfg.set('node',field,val)
  File "/home/pi/PiGI/software/pyGI/configurator.py", line 100, in set
    self.dynamic_conf.set(section,option,value)
  File "/usr/lib/python3.7/configparser.py", line 1197, in set
    self._validate_value_types(option=option, value=value)
  File "/usr/lib/python3.7/configparser.py", line 1182, in _validate_value_types
    raise TypeError("option values must be strings")
TypeError: option values must be strings

[dadosch]

Now everything should work. @chron0 could you test?