non-tagged value in register eax was pushed to the stack.

Fixed potential quadratic behavior when converting strings to numbers.

Fixed bug where the return value from Object::SetProperty could end up
being the property holder instead of the written value.

Improved debugger support by allowing nested break points and by
dealing with stack-overflows when compiling functions before setting
break points in them.


git-svn-id: http://v8.googlecode.com/svn/trunk@4 ce2b1a6d-e550-0410-aec6-3dcde31c8c00