Merge pull request #89 from Ptizef/master

Addressing Flyspray tasks
Correct S57 UTF-16 National text string conversion.
Correct S57 "Leading light" sector display (FS#1315)
Correct sorting of "Trk" column in AIS target list (FS#1304)
Correct Sydney, Australia time zone constants.  (FS#1298)
Correct parameter tracking logic in GRIG PlugIn (FS#1307)
Improve Chart Group internal logic coherency checks
Remove printf
Relax "leading light" max sector width from 15 to 60 degrees (FS#1315)
Dashboard, implement WMM_PI JSON message decoding for Mag Variation input. (FS#1310)
Extend auto timeout on PlugIn Message Box
Improve internal triangle tesselator performance.
Implement No-OpenGL cm93 chart rendering.
Correct Mac build error in wxJSON
Improve dialog Z-order logic for Mac.
Correct MSVC build error.
Dashboard, calculate HDT from HDG message if variation is available.
Add DC validity checking to s52plib::RenderHPGL()