Feature #8725: Fast rendering of geom (v-OGR)

Implements fast rendering of LineStrings and Polygons pre-applying a
view threshold filter to the geometries to render in qgis. Also disable
'Antialiasing' when it is possible.

View Table of test results in 'http://hub.qgis.org/issues/8725'

(This version of branch implements the improvement in vector-providers)