Merge pull request #295 from leprechau/master

fix compilation error in rlm_ruby
Allow forcible empty expansions
The "opaque" data belongs to handler, not to reply
if len==0, buff may be NULL
Use paircursor for iteration where appropriate
Fix use after free when iterating over pairlists to be freed
VERIFY must only be be called on non-NULL pointers

pairfindnext needs its own pointer to work correctly

Fix typo in evaluate.c
Macro
Fix reference issues hidden by cast
And one more...
Need more cursors
Update main autoconf

Better check for -Qunused-arguments

Pass -Wdocumentation if supported by the compiler, this allows clang >= 3.2 to parse the doxygen documentation and emit warnings if it doesn't match the code.
Fixup doxygen comments to pass new check
-Wdocumentation doesn't warn about unrecognised tags
Probably need to pass -Werror for compiler argument checks
and just use cflags
Remove extraneous brackets
Document the "limit" section, and move max_pps there
Add "skip_duplicate_checks" for detail && tcp listeners
Use correct dependencies when re-building "configure"