start on ruby code generator

have arrays and some language constructs
added an embedded host form that means 'plain code'

Now have three forms:
 1. Plain code
 2. Statement blocks (can be wrapped in {} in C)
 3. Expression blocks (can be wrapped in () in C)
add block delims to embedded host in lang-specific code gens

Was doing this in the lang-indep code generator and always using {}. Need to
stop this with ruby code generator.
replaced ++ and -- with += 1 and -= 1
a couple ruby syntax fixes
ruby: declare ints using 'v = 0' syntax