- various mods: host and URI escaping:

      Be sure to escape potential troubled strings,
  add missing html escaping
- const fixes for mod_imagemap

Submitted by: jim, sf, covener
Backported by: rjung
Reviewed by: rpluem, wrowe

Backport of r1413732, r1418752, r1416889, r1422234 and r1422253
from trunk resp. r1418941 and r1425750 from 2.4.x.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1447390 13f79535-47bb-0310-9956-ffa450edef68