Added placeholder properties to xAxis so they show in documentation

Fixes #110
removed options.bar.padding to options.bar.groupPadding for consistency with column chart

Relates to issue #42
Merge pull request #118 from forio/documentation

explanation for #106
Added parameter to control the duration of the animations

Fixes #115
Release 0.0.63
Merge branch 'master' into documentation
yAxis.labels.align --> verticalAlign (#108)
docs for #77 being fixed