add rubygem popen4 as a build dependency
fix build errors w/ core libraries
fix examples for recent language changes

comments are fixed now, plus some instruction parameters are now up to date
update documentation for the if instructions
remove docs for branch comparison instructions

these instructions are going to go away so killing the docs first
so less likely anyone misses them after they go.
will be removed in favor if comparison
instructions with no branching + the regular if instructions.