Add support for more sequence types

Add support for more sequence types

This commit adds support for more sequence types by adding a sequence
wrapper.  This class enables conversion between v8::Array and C++
sequences of various types (currently just QList<int>, QList<qreal>,
QList<bool>, QList<QString>, QList<QUrl> and QStringList), but more
types can be added later if required).

When a JavaScript object is created from such a sequence, its
prototype object is set to the v8::Array prototype object.  The
indexed setter, indexed getter, length and toString methods are
implemented directly or in terms of the underlying sequence resource.

Note that currently, sequences of ValueTypes are NOT supported, due to
the fact that operations like:
     someObj.someValueTypeSequence[i].x = 5;
would not behave as required.

Task-number: QTBUG-20826
Task-number: QTBUG-21770
Change-Id: I36deb448fb0e87a32084a900e70a2604ff369309
Reviewed-by: Chris Adams <christopher.adams@nokia.com>