Add courtyards around 0.1" PTH header footprints

[sfe-SparkFro]

First off, all footprints should really have a courtyard to ensure DRC catches any accidentally overlapping parts.

Second, if a user wants to solder headers onto a board, there needs to be clearance for the headers, which are 0.1" wide. It's easy to forget this when designing a tight layout, such as the instance below (the outer 2x 0402 footprints would interfere with a header)

Just need to add courtyard rectangles 0.1" wide like so: