fix type-o regarding the active port in the forking ROT13 example.
Merge pull request #18 from kenlittle/master

fix type-o regarding the active port in the forking ROT13 example.
Correct description of second evdns_base_new() argument

The doxygen correctly described its allowed values as 1/0, but we were
saying here that it took true/false.
Fix some typos
Fix another typo

(found using cat *.txt |tr -cs A-Za-z0-9_ '\n' |sort |uniq -c |sort -n |less)
Fix another semi-automatically detected typo