Updated tutorial & library! I2C/SPI backpack guide

We’ve been hard at work doing a lot of upkeep on our Arduino libraries & tutorials. One of the ones we did today was the I2C/SPI backpack guidehttps://learn.adafruit.com/i2c-spi-lcd-backpack and the library that goes with ithttps://github.com/adafruit/LiquidCrystal We updated LiquidCrystal to Adafruit_LiquidCrystal so it doesn’t conflict with the built in LiquidCrystal. If...