Update link to docs.
Update optional dependencies and peg 'requests' version.
Move code generation utilities from VI firmware repo to Python lib.
Fix imports.
Include signals.cpp header/footer in package distribution.
Merge branch 'master' into next
Add code generation to changelog.
Enable CLI logging when generating code.
Use proper XML-backed subclasses of Message and Signal.
Put most likely search path first (the default).
Fix searching for files in a list of directories.

Using the same variable name was causing it to change each time through
the loop.
Fix incorrect dict key usage.