README section on contributing.
Improve contribution section.
Remove the copyright notice.
Title value for SVG element containing actual data value.

Unfortunately this only seems to work in Firefox (according to my
tests). I've submitted a Chromium bug that hopefully will get it
fixed: https://code.google.com/p/chromium/issues/detail?id=170780
Merge branch 'gh-pages' into sparklineify

Conflicts:
	bar.svg
	circle.svg
	line.svg