Eliminate last v8 dependency from QV8SequenceWrapper

Stub out file name and line number information in QV4::ExecutionContext,
used for warning generation.

Change-Id: I922541e1ee4a5e2211ca6c16494d2b9044a9c346
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Fold qv8sequencewrapper_p_p.h into qv8sequencewrapper.cpp

Most of the implementation belongs into a C++ file instead of a header file,
it's not re-used from anywhere else.

Change-Id: Ib41e3e104d9544710343b869116368bbca999622
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Finalize sequence wrapping

* Move into QV4 namespace
* Get rid of sequence wrapper instance, all static methods now

Change-Id: I9a9e7ce10890cfe4625b3571bdb4b0ffec34658a
Reviewed-by: Lars Knoll <lars.knoll@digia.com>