This commit is mainly about introducing Lua functions to allow more powerful scripts.  1) All LuaScriptInterface::getField functions now give the programmer (sourcecode) the possibility to check for missing values; 2) Now distance of target as well as the range of distance attacks is a dynamic variable and can be controlled by the Lua scripter; 3) Added some Lua functions allowing very advanced (and probably not useful for most scripters) management of fields and conditions; 4) Added some Lua functions giving more information about itemtypes (getItemBreakChance, getItemShootRange and etc) and some miscelaneous functions (getAllItems); 5) Added a more powerful version of doTargetCombatHealth(no support for callbacks).