x axis log scale.
Merge branch 'master' into xlog

Conflicts:
	dygraph-layout.js
dingle quotes.
Execute custom shapes closure
Merge pull request #297 from pshevtsov/custom-shapes

Execute custom shapes closure. Makes tests/custom-circles.html work.
Mind renaming.
Merge pull request #296 from danvk/xlog

Log along the x-axis (bug 189)
Merge branch 'master' of git://github.com/danvk/dygraphs