v0.9.0

The summarized version of the changelog is the following:

• Fix text encoding once and for all (unit tests were added in a separate repository that also includes a "control panel" for testing packets)
• Add text color conversion and stripping
• Include GIS variables for every packet and struct using physical values (see README for more details)
• Add utility functions for unit conversion
• Fix a bunch of errors in various packets

The next release should hopefully include InSimRelay as well as more fixes for packets used on hosts, as I haven't been able to test those yet.