Rather than producing separate files for each module, the default build now
produces a single file. This should encourage better page-load performance as
the files were relatively small. Also, it's easier to deal with only one file
rather than many, especially if you're not quite sure what the dependencies are.
You may still create minimized builds, if you don't want every feature.
This commit also demotes the chart components to the examples directory, rather
than keeping them as part of the core library. As always, D3 is not a charting
library, and these were ever only intended to serve as examples.
Fixes#428. This is built on top of existing tick support for linear scales: for
small intervals, a linear scale computes ticks based on milliseconds; for large
intervals, a linear scale computes ticks based on fractional years. This commit
also extends the time scale's formatter to display milliseconds.