BUG: Old errors cause new HDAPI devices to appear to fail

The HDAPI error stack persists across device instances, so the error
stack should be flushed before initializing a new device and checking
for initialization errors.  Otherwise, a fatal error is thrown even if
the device intializes correctly

Base/Devices/imstkHDAPIDeviceClient.cpp

@@ -35,6 +35,10 @@ HDAPIDeviceClient::init()
 {
     m_buttons = std::map < size_t, bool > { { 0, false }, { 1, false }, { 2, false }, { 3, false }};
 
+    //flush error stack
+    HDErrorInfo errorFlush;
+    while (HD_DEVICE_ERROR(errorFlush = hdGetError())){}
+
     // Open Device
     m_handle = hdInitDevice(this->getDeviceName().c_str());