Adding README information

Signed-off-by: Thibaut VIARD <[email protected]>

Author: aethaniel

README.md

@@ -1,2 +1,8 @@
 # ArduinoModule-CMSIS
-CMSIS module for Arduino IDE
+ARM CMSIS module for Arduino IDE
+
+Source is the one provided by ARM at https://github.com/ARM-software/CMSIS/
+
+Main CMSIS URL is http://www.arm.com/products/processors/cortex-m/cortex-microcontroller-software-interface-standard.php
+
+API Help can be found at http://www.keil.com/pack/doc/cmsis/general/html/index.html