Get rid of v8::String::(Ascii)Value

Change-Id: I792a94590efbec852620d101b620b263a90e1d54
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Remove v8 dependencies in qhashedstring

Also remove now unused API in v8::String

Change-Id: I2570aedf407c89ad85da01cf0e2153a52b4e562d
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Add correct filename and line number info to v8::StackFrame

Change-Id: I14d4e1b78d62fd7ccf19a57d14a5a32df9385037
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>