Add WQFN-20-1EP_4x4mm_P0.5mm_EP2.7x2.7mm
This is a footprint for TPA6130A2RTJ (KiCad/kicad-symbols#1621).
Generated by a script: https://github.com/pointhi/kicad-footprint-generator/pull/475 Datasheet: http://www.ti.com/lit/ds/symlink/tpa6130a2.pdf#page=38
KLC violations reported for the two footprints are also reported for already existing footprints in the library.