Decrease error severity for Altium imports

These are not errors that end users can do anything about.  Keep them
around for developer debugging if we want to see more imformation but
don't pop up error messages on the user's screen

common/io/altium/altium_binary_parser.cpp

@@ -361,7 +361,7 @@ std::map<wxString, wxString> ALTIUM_BINARY_PARSER::ReadProperties(
 
     if( !hasNullByte && !isBinary )
     {
-        wxLogError( _( "Missing null byte at end of property list. Imported data might be "
+        wxLogTrace( "ALTIUM", wxT( "Missing null byte at end of property list. Imported data might be "
                        "malformed or missing." ) );
     }
 

common/io/altium/altium_props_utils.cpp

@@ -93,7 +93,7 @@ int32_t ALTIUM_PROPS_UTILS::ReadKicadUnit( const std::map<wxString, wxString>& a
 
     if( !value.EndsWith( "mil", &prefix ) )
     {
-        wxLogError( _( "Unit '%s' does not end with 'mil'." ), value );
+        wxLogTrace( "ALTIUM", wxT( "Unit '%s' does not end with 'mil'." ), value );
         return 0;
     }
 
@@ -103,7 +103,7 @@ int32_t ALTIUM_PROPS_UTILS::ReadKicadUnit( const std::map<wxString, wxString>& a
 
     if( !prefix.ToCDouble( &mils ) )
     {
-        wxLogError( _( "Cannot convert '%s' to double." ), prefix );
+        wxLogTrace( "ALTIUM", wxT( "Cannot convert '%s' to double." ), prefix );
         return 0;
     }