Corrected LCD only error

If only an LCD is defined and no menu or keyboard defined, there is a
compilation error.

Added conditional compilation.

Marlin/BlinkM.cpp

@@ -0,0 +1,29 @@
+/*
+  BlinkM.cpp - Library for controlling a BlinkM over i2c
+  Created by Tim Koster, August 21 2013.
+*/
+#include "Marlin.h"
+#ifdef BLINKM
+
+#if (ARDUINO >= 100)
+  # include "Arduino.h"
+#else
+  # include "WProgram.h"
+#endif
+
+#include "BlinkM.h"
+
+void SendColors(byte red, byte grn, byte blu)
+{
+  Wire.begin(); 
+  Wire.beginTransmission(0x09);
+  Wire.write('o');                    //to disable ongoing script, only needs to be used once
+  Wire.write('n');
+  Wire.write(red);
+  Wire.write(grn);
+  Wire.write(blu);
+  Wire.endTransmission();
+}
+
+#endif //BLINKM
+