Adding ER diagrame

Current relation of our schema, need to be reviewed, and drwa with host
limitation
Fix ARM compilation.
-Upd configure (merge with Hercule configure.in)
-upd nullpo.c and atomic.h to allow arm compilation, testedon Epiphany parallela.
Merge branch 'master' of https://github.com/rathena/rathena
Update Model_Relation

-Export project to Visual_Paradigm
--add package overlay to see host dependancy
Update itemdb_subcheck fonction

now return bool instead int as they're value only true or false.
Update rathena modele class in rathena.vpp
Update nullpo, to avoid va_list empty creation.
Update classe model
Bug Fixes
* Fixed the cash shop stacking non-stackable items upon purchase. (bugreport:7580, bugreport:7879, bugreport:8224)
* Fixed an issue with selling pet eggs in the cash shop (Hercules d57781c)
* Cleaned up some compile warnings from CPPCheck. (bugreport:9043)