* caclulation of resolution factor no longer depends on proj4js,
* created a member variable for the resolution factor and moved the calculation of the resolution factor to createMap(),
* created acceptance test (tests/manual/overviewmap-projection.html).
r=me (closes#1620)
git-svn-id: http://svn.openlayers.org/trunk/openlayers@7864 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf