* declared intwidth, fracwidth, and is_signed UDPs
* fix boolean type name in UDP definition
* generate hwif fields with fixedpoint indices
* make "counter" and "encode" properties mutualy exclusive with signed/fixedpoint
* add signed/unsigned to hwif
* improved fixedpoint error messages, added validation tests
* added fixedpoint tests
* fixedpoint/signed not allowed for signal components
* added signed/fixedpoint UDP docs
* handle single-bit fixedpoint numbers
* fix too many positional arguments lint
* changed spelling of fixedpoint to fixed-point
* use "logic" in place of "unsigned logic"
* split signed and fixedpoint docs, added examples
* allow enums with is_signed=false
* split signed and fixedpoint implementations
* assorted nits picked
* updated is_signed validation unit test
