'getwork' protocol fix

Can you add the following line to "main.cpp" to fix the 'getwork' protocol?

[...]
 int jhMiner_main_getworkMode()
 {
+	threadHearthBeat = (DWORD *)malloc( commandlineInput.numThreads * sizeof(DWORD));
 	// start threads
 	for(sint32 threadIdx=0; threadIdx<commandlineInput.numThreads; threadIdx++)
[...]

thank you.

- Thomas