Change binary dir to be binary dir for all OS

Linux did not see AppDataLocation as the binary directory, but as an
arbitrary dir in the home folder.

src/utils/paths.h

@@ -9,7 +9,6 @@ using std::string;
 
 optional<string> binaryDirectory();
 optional<string> binaryDirectoryFindFile( string fileName );
-optional<string> binaryDirectoryFindDirectory( string directoryName );
 
 optional<string> settingsDirectory();