improve zooming functionallity for wheel and toolbar
use sse2 cflag rather than sse
Merge pull request #116 from seandepagnier/optimum-merging

Optimum merging -- a few more updates and corrections
3.3.1715
Correct and harmonize raster chart region calculation for skewed charts.
Set OpenGL texture compression options to default "OFF"
corrections to opengl route rendering
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN into optimum-merging
Correct S52Plib raster symbol table initialization sequence.
Merge pull request #118 from seandepagnier/optimum-merging

Optimum merging -- improved corrections from chucksk for route rendering
Fix end of NMEA sentence received from a datastream in case no checksum is present
Correct OpenGL Route/Waypoint rendering logic
Merge branch 'master' of github.com:OpenCPN/OpenCPN
Correct canvas Refresh() logic when OpenGL FBO is in use.
Eliminate flashing on Windows OpenGL canvas rollover & Refresh().