Nyall Dawson 51035cfb67 Add optimised constructors for QgsLineString
Instead of requiring all linestrings to be constructed by
first creating QgsPointSequence (requiring creation or
conversion of points to QgsPointV2), allow construction
of LineStrings directly from vectors of values (fastest!)
or lists of QgsPoint.

Likely results in speedups for lots of geometry operations,
but using the same layer as earlier tested for densify
improvements the densify operation time dropped further
from 25 seconds to 15 seconds.
2017-03-25 20:44:31 +10:00
..