Bigger holes, lower power, and many small improvements

• Standard through-holes were a little optimistic for placing over already-soldered (and possibly bent) pins. Now they're larger. After testing, these are much nicer.
• Updated resistor dividers in front of LMH1251 to reduce current consumption by ~15mA (without impacting output quality).
• Made over 100 small changes to the board layout, almost all of which were suggested by MrPix from the AtariAge forums. The most notable improvement is to the overall continuity of the VCC fill on the top layer but many others are nearly as good.