Added architecture specific definitions in library.properties

Fix #31

Author: cmaglie

library.properties

@@ -6,4 +6,4 @@ sentence=Enables reading and writing on SD cards.
 paragraph=Once an SD memory card is connected to the SPI interface of the Arduino or Genuino board you can create files and read/write on them. You can also move through directories on the SD card.
 category=Data Storage
 url=http://www.arduino.cc/en/Reference/SD
-architectures=*
+architectures=avr,sam,samd,arc32