add svg drop-shadow filter

-moz-box-shadow dont seam to works anymore
Merge pull request #41 from yukulele/patch-1

add svg drop-shadow filter
moved redundant absolute positioning to common styles
adjusted unittests to reflect changes
better handling of zero border width case
Merge pull request #44 from bra1n/master

Move redundant absolute positioning to shared styles and handle zero border width better
remove arrow box drop shadow
deploy
Merge pull request #1 from hojberg/master

Updates