Gravitational Field full official implementation and minor fixes
- Gravitational Field will now work as official servers (bugreport:4897)
  * Fixed range of Ganbantein (16->14) and Gravitational Field (9->14)
  * Gravitational Field never misses and can hit hidden targets
  * Similar to Pressure the damage can not be increased or decreased by any means, it even hits GTB users and users protected by Devotion/Sacrifice
  * Renewal damage is now 400+100*level every 500ms (200+200*level every 1000ms in pre-renewal)
  * You can no longer do normal attacks while the skill is active
  * You now can use skills while the skill is active, however, other skills are unable to deal any damage as long as Gravitational Field is active
  * Added the possibility to link different skill unit groups together; if a skill unit group gets deleted, the linked skill unit groups are deleted as well; this was needed because when being hit, all Gravitational Fields of the person being hit need to be removed
  * Gravitational Field can no longer overlap with itself
  * Pressure and Gravitational Field will now be considered "physical normal attacks" and can consequently trigger Autospells; unlike manually cast spells, Autospells can deal damage while Gravitational Field is active
- Fixed that in renewal, weapons with a range of 2 and 3 did depend on DEX instead of STR (fixed #129)
  * Special thanks to NovaRagnarok for the fix