Add SMD LDO part

Added symbols & footprint with correct pinout for LM3480 via [LM3480 -- "100 mA, SOT-23, Quasi Low-Dropout Linear Voltage Regulator"](http://www.ti.com/product/lm3480).

Note: Haven't replaced the existing SMD regular on the schematic due to the line-ending and weird text placement issue. Also haven't entirely tested that the symbol & footprint work together due to issues caused by missing libraries.