Scripted SIL0008D MicroSiP Package

replaces #931

Script PR: https://github.com/pointhi/kicad-footprint-generator/pull/258

http://www.ti.com/lit/ds/symlink/tps82130.pdf#page=19

Texas_MicroSiP-8-1EP_2.8x3.0mm_P0.65mm_EP1.9x1.1mm_ThermalVia:
  device_type: 'MicroSiP'
  library: Package_LGA
  manufacturer: 'Texas'
  part_number: 'SIL0008D'
  size_source: 'http://www.ti.com/lit/ds/symlink/tps82130.pdf#page=19'
  ipc_class: 'qfn_pull_back'

  body_size_x:
    minimum: 2.7
    maximum: 2.9
  body_size_y:
    minimum: 2.9
    maximum: 3.1

  lead_width:
    minimum: 0.38
    maximum: 0.42
  lead_len:
    minimum: 0.48
    maximum: 0.52
  lead_to_edge:
    nominal: 0.1
    tolerance: 0

  EP_size_x:
    minimum: 1.0
    maximum: 1.2
  EP_size_y:
    minimum: 1.8
    maximum: 2.0
  EP_num_paste_pads: [1, 3]

  thermal_vias:
    count: [1, 3]
    grid: 0.75
    drill: 0.2
    paste_via_clearance: 0.1
    EP_num_paste_pads: [1, 3]
    EP_paste_coverage: 0.85
    paste_avoid_via: False

  pitch: 0.65
  num_pins_x: 0
  num_pins_y: 4