changes needed for wx-3.0, also tested with wx-2.8
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN into wx-3.0
Merge pull request #106 from seandepagnier/wx-3.0

changes needed for wx-3.0, also tested with wx-2.8
Merge pull request #108 from Ptizef/master

Apply global colours scheme on dialogs and overlays  #FS232
Correct to avoid potential deref(0) crashes.
Add missing forward declaration.
Improve/update PlugIn blacklist contents and runtime reporting.
Update wxWidgets library dlls to enable PDB debugging.
'Numbers' background coloured according to values (#FS1338)
(also suppress redundant calculation and useless code)
Add third choice for direction arrows (#FS 1338)