avoid overlapping "Dummy" symbols

reported by James Jackson in message:
  [Ngspice-users] Problem building git head --with-ngspice Mac OS X
devices/hisimhv1, devices/hisim2, avoid overlapping globals TMF1 ... TMF6

reported by James Jackson in message:
  [Ngspice-users] Problem building git head --with-ngspice Mac OS X
remove unused code
complete "remove unused code"
.control and `B' parser, fix precedence of '-' versus '^'

-2^2 shall be -(2^2) instead of (-2)^2
update bison generated files
xpressn.c, fix `truth' for ternary_fcn()

0.0 is `false', everything else is `true'
xpressn.c, whitespace cleanup
xpressn.c, fix semantics of '&&' and '||'

these shall interpret a value as a bool according to (value != 0)
and these shall evaluate to either 1.0 or 0.0