Cleaned up pin descriptions on a few components

Hi Folks,
In this pull request I have changed the pin names on the symbols and layouts for Pro Mini, Pro Micro and a couple of others.  These changes are to bring the labeling in line with the boards these components are intended to represent.
Changed occurrences of RX1 to RXI
Changed occurrences of TX0 to TXO
Changed occurrences of GNDn to GND@n
Changed occurrences of RSTn to RST@n
Added "*" to PWM enabled pins on Pro Mini and Pro Micro

If this isn't the sort of edits you are looking for, feel free to say "no thanks".

Thanks,
Chip