Update STM32F4/libraries/*/library.properties to get rid of Category not valid IDE warnings

Author: ozayturay

STM32F4/libraries/RTClock/library.properties

@@ -4,5 +4,6 @@ author=Various
 email=
 sentence=Real Time Clock
 paragraph=Real Time Clock for STM32F4
+category=Other
 url=
 architectures=STM32F4

STM32F4/libraries/SPI/library.properties

@@ -4,5 +4,6 @@ author=Roger Clark
 email=
 sentence=Serial Peripheral Interface
 paragraph=SPI for STM32F4
+category=Communication
 url=
 architectures=STM32F4

STM32F4/libraries/arduino_uip/library.properties

@@ -3,6 +3,7 @@ author=ntruchsess
 email=Norbert Truchsess <norbert.truchsess@t-online.de>
 sentence=Ethernet library for ENC28J60
 paragraph=implements the same API as stock Ethernet-lib. Just replace the include of Ethernet.h with UIPEthernet.h
+category=Communication
 url=https://github.com/ntruchsess/arduino_uip
 architectures=STM32F4
 version=1.04