Fix #78: CPUX64 not implemented MyAllMethodsHandler

Please note that x64.inc changes is from commit "Merge branch 'master' of github.com:remobjects/pascalscript".  I found the recent changes to x64.inc fail #87.

In this commit, I remove call to StoreStack(p^, Pointersize2) and replace by StoreReg(IPointer(p)).  I do not know the impact and side effects.

I also implement MyAllMethodsHandler for CPUX64.  However, there are two parameters (Stack and _ECX) used by
function MyAllMethodsHandler2(Self: PScriptMethodInfo; const Stack: PPointer; _EDX, _ECX: Pointer): Integer; 
is not passing through.  I can't find example how to use these two parameters in function MyAllMethodsHandler2.