Added category to libraries used in the test-suite to silence warnings

Signed-off-by: Cristian Maglie <c.maglie@arduino.cc>

Author: cmaglie

src/arduino.cc/builder/test/libraries/SPI/library.properties

@@ -7,4 +7,5 @@ paragraph=
 url=http://arduino.cc/en/Reference/SPI
 architectures=avr
 types=Arduino
+category=Other
 

src/arduino.cc/builder/test/libraries/USBHost/library.properties

@@ -6,3 +6,4 @@ sentence=Allows the communication with USB peripherals like mice, keyboards, and
 paragraph=The USBHost library allows the board to appear as a USB host, enabling it to communicate with peripherals like USB mice and keyboards. USBHost does not support devices that are connected through USB hubs. This includes some keyboards that have an internal hub.
 url=http://arduino.cc/en/Reference/USBHost
 architectures=samd
+category=Other

src/arduino.cc/builder/test/libraries/wronglib/library.properties

@@ -6,3 +6,4 @@ sentence=sentence
 paragraph=paragraph
 url=url
 architectures=*
+category=Other