support varying-length series for lines
tweak doctype for multiple length example
refactor domain discovery to support series with varying lengths
Merge branch 'master' into multiple-length
don't smooth when there's no smoothing to be done
support null y-values representing gaps in data
support varying x-values across series
fix up "inconsistent" example; only check series lengths when stacking
Use number formatting also for negative numbers

Use formatKMBT and formatBase1024KMGTP also for negative numbers
Merge pull request #152 from marcospri/patch-1

Use number formatting also for negative numbers
Moves highlighted series to top for line and scatter.
move highlighted series to the top for all unstacked renderers; fix for area renderer; fixes #151
make legend labels play nicely with Bootstrap; fixes #144
Merge branch 'master' into multiple-length
don't try to render null values in various renderers
remove debugging in Rickshaw.Series
add tests for Rickshaw.Series.fill
add tests for throwing errors for trying to stack inconsistent series
[#160] Fix Rickshaw.Graph.HoverDetail#render missing graph reference
[#160] Restore API compatibility