Appveyor build fails

[rgleason]

C:\project\projections_pi\src\rtlsdr_pi.cpp(356): warning C4305: 'argument' : truncation from 'double' to 'GLfloat' [C:\project\projections_pi\build\rtlsdr_pi.vcxproj]
C:\project\projections_pi\src\rtlsdr_pi.cpp(665): warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning) [C:\project\projections_pi\build\rtlsdr_pi.vcxproj]
C:\project\projections_pi\src\rtlsdr_pi.cpp(878): error C2668: 'wxConfigBase::Read' : ambiguous call to overloaded function [C:\project\projections_pi\build\rtlsdr_pi.vcxproj]

Line 878  

m_bEnableFlights = pConf->Read ( _T ( "EnableFlights" ), false );
m_Dump1090Server = pConf->Read ( _T ( "Dump1090Server" ), "127.0.0.1" );

Also using wxWidgets 3.0.2 and OpenCPN v5.0 uses wxWidgets 3.1.2

Whereas there are two pull requests from March for Ov42 and Ov50 that compile. They are now largely outdated and may have conflicts.