This patch fixes the following bugs in the vlog95 converter:
When emitting a signal as an expression, if the signal is local then
emit the expression that is driving the local signal.
The casts need to emit the expression.
When emitting pull devices they have different default strength rules
(pull is the default).
For compatibility pull devices should only have a single output net.
Extend the code that searches for the <var> = <delay> <value> pattern
to also check for an <event>. The previous event code only looks for
the repeat event pattern.