Fix self._min and self._max
Quick hack for addressing issue #30.

svg.py: Added the viewBox height by 20 so that I can put X-Axis title
there.
config.py: Added xtitle and ytitle for giving title name for the
respective axes.
graph.py: Added functions _x_title() and _y_title() which adds title
for the respective axes.
Fix x/y title margin computation + split if too long + position with legends
Add trigonometric interpolation from redditor viscence
Add lagrange interpolation and hermite variants
Add render_sparkline shorthand function and some config to make it possible
Merge all css in one tag as a workaround for inkscape one style tag bug. Fixes #7
Minor fixes + add darken and lighten functions to style, which are broken btw
start style of color
Merge branch 'master' of github.com:Kozea/pygal
Fix darken/lighten
Add test case for issue #35
Merge pull request #35 from dzen/master

Force self._min and self._max to be zeroed instead of None
Merge branch 'master' of github.com:Kozea/pygal
Fix tox.ini since numpy/scipy is no more used
Fix sparktext
Fix sparktext Python3...
Fix sparktext Python3... 2nd edition
Add some color helpers
to do 7 variations color for charts