Dynamic node removal on "remove" for standard graphs

Removes the chart, select and sidebar nodes, and changes the URL
*without* reloading the page or the data.

Pending implementation for standard, horizon
add autoremove functionality for stacked.

some changes to the general function. pending sanitation of process
add remove for horizon
close button appending dynamically to title. Doesn't appear to break much, but css is hardcoded to length (for now)
Merge branch 'master' into superremove
correct back button logic when rewriting history.
when using back, actually go to the pushed state. Appears to work for both rewritten and normal history
Retroactively remove metric url content from buttons

The button's urls are created at page load, which include references to
metric count = n (n -1 in cases of sidebar remove buttons). When n
reduces to n-1, the number of metrics in all these buttons also needs to
change. So, take all urls on the page containing the metric name and
remove it from their href query string.
Only reload the page if the back button was pressed after a manual pushState event

Without this, normal page reloads refresh the page twice. Normal humans
can't see this change (happens to quickly), but Capybara chucks a right
fit and gets very upset.
Merge pull request #51 from anchor/superremove

Dynamic node removal on "remove" for standard graphs