Add UI hooks for callgraph viewing.
Use user's date format.

This makes date formatting more consistent.
Start stubs for callgraph UI.
Naive implementation of getting a callgraph.

Using recursion is probably a bad idea, but it will help with
prototyping and building out the UI.
Merge remote-tracking branch 'origin/get-callgraph' into view-callgraph

Conflicts:
	web/Xhgui/Profile.php
Fix notice error.
Trim wrapping array off.

It makes rendering the chart harder.
Initial pass at implementing a very basic callgraph tree.

Basically copied from the d3.js examples, but it is a start, the current
code hits PHP memory limits pretty easily as json_encoding the callgraph
can easily exhaust all the memory allocated to PHP.
Exclude functions that are less that 1% of the total run time.

Functions that less than 1% of the runtime will just add noise to the
graph and make reading data harder.
Remove stray </li>
Make chart a bit more readable.
Fix incorrect time display.
Add % values to each node in the callgraph.

These values can be used to generate circles of various sizes in the
callgraph.
Scale dots based on % of wall time used.
Position tooltips correctly.

Get tooltips with value + function name in the correct place.
Hide/show & position text.

Only show text for big nodes, simplify the attr/style calls.
Color nodes by value.

More expensive nodes are darker now.
Filter duplicate subtrees out.

Remove duplicate subtrees, as xhprof cannot give useful information for
grandchild methods. We'll draw the graph as all calls came from the
first parent. This is a bit of a lie, but there is no way for us to sort
out the data based on what xhprof gives us.
Show an additional 1% of methods.

Now that duplicate subtrees are not being rendered we can show more
detail.
Merge pull request #31 from preinheimer/view-callgraph

View callgraph