Merge pull request #2 from dforsi/master

Fix wrong position of box around pin 1 for DIP
add mirror capability
add soh - surface mount dual row header, silk_line
Add refdes string to kicad format
move examples to their own folder, unit conversions
add PCI express fingers example
use defaults for solder mask clearance and copper clearance rather than hard coding
add capability to set mask clearance
add_pad, add_via, doc strings
add polygon support to Kicad
round all outputs to 1 nm, fix improper rounding of negative values in gEDA output