Need to compute the low and high character-space keys from the condition-trans

Need to compute the low and high character-space keys from the condition-trans
overlap when computing an expansion. Can't use the range supplied from the
condition overlap since they may not match. An incorrect machine that accepted
1(!cond1, !cond2) was generated for the following grammar.

c = 2 @matched_c;
sc1 = 1..2 when cond1;
sc2 = 1..2 when cond2;
main := sc1 | c | sc2;

This bug was reported by Tim Chklovski.

git-svn-id: http://svn.complang.org/ragel/trunk@422 052ea7fc-9027-0410-9066-f65837a77df0