Renamed some variables forgotten when adding the battleground interface

- Follow-up to 35c131c
- Fixes bugreport:7721, thanks to purityz, Dastgir Pojee
  http://hercules.ws/board/tracker/issue-7721-lastest-update-make-map-crashing-on-battleground/

Signed-off-by: Haru <haru@dotalux.com>
Merge branch 'master' of https://github.com/HerculesWS/Hercules
Renamed more forgotten variables during interface conversions

(related: b9c8f57)
Most renames are trivial (just to avoid shadowing global variables, even
if they currently did no harm), but there were some cases of partly
renamed variables that caused some NULL checks to always pass and who
knows what could have been happened when they were too subtle to make
the application crash.

Also corrected some potentially unsafe macro definitions

Signed-off-by: Haru <haru@dotalux.com>
Renamed iDuel interface to duel

- Note to plugin developers:
  change your GET_SYMBOL("iDuel") to GET_SYMBOL("duel").

Signed-off-by: Haru <haru@dotalux.com>
Renamed local variables that would conflict with a rename of iTimer to timer

Signed-off-by: Haru <haru@dotalux.com>
Merge branch 'master' of https://github.com/HerculesWS/Hercules
Updated Hercules
Added Custom Valkyrie Set for the Guild Package
Added authority for group ID 4 = test GM to start events and itemizer