Linux/MacOSX:check that the requested size of file container is less than available

disk free space. Add a CLI switch to disable this check.

src/Main/CommandLineInterface.h

@@ -83,6 +83,7 @@ namespace VeraCrypt
 		VolumeType::Enum ArgVolumeType;
 		bool ArgTrueCryptMode;
         shared_ptr<SecureBuffer> ArgTokenPin;
+        bool ArgDisableFileSizeCheck;
 
 		bool StartBackgroundTask;
 		UserPreferences Preferences;