Project parser speed and memory usage improvements, float conversion fixes, dependency updates

v0.11

  - ignore intermediate syslog I/O errors

v0.9 - DPT fixes in ETS4 project parser

- attempt to reduce memory usage during project loading a bit

Syslog supprt, Memory optimization

v0.7

Merge branch 'master' of https://github.com/owagner/knx2mqtt.git

v0.5 - ETS4 project parsing and proper DPT conversion

• now capable of reading ETS4 project files to determine both group address names and
  their DPT values. Obsoletes "knx.groupaddressfile"
• now properly converts incoming and outgoing messages according to the specified
  data point values.
• includes JSON attribute "knx_textual" with a textual representation of the DPT value