This patch add the following functionality to the vlog95 generator.
Add support for most CAs. Selects still don't work correctly.
Emitting a named event as an expression.
Enhance the ability to find a signal in a nexus.
Add code to emit a nexus driven by a constant.
Rework the delay/strength code for logic gates/CAs
Refactor some of the number code.
Refactor the variable emitting code to support named blocks.
Translate the compiler code back to <var> = <event> <value>