Xhgui 0.4.0

It has been far too long since a proper release of XHGui so this is a big one.
I hope to make future releases more frequent and smaller. The changes you can
expect in 0.4.0 are:

* A default config file is now available.
* The provided config file is now empty, this should help prevent conflicts in the future.
* The `simple_url` config option has been added. This option lets you provide
  a callback that can be used to generate the short URLs that xhgui uses to group
  runs together.
* Improved layout and many visual bug fixes.
* Improved callgraph display.
* Xhgui is now available on packagist.org.
* The callgraph view can generate graphs for any metric now.
* Improved symbol view.
* Exclusive is now called Self. This better matches terminology used in other
  profiling tools.
* You can search through run functions when viewing an individual run.
* uprofiler is now supported.

Xhgui v0.3.0

Xhgui 0.2.0

Xhgui hooks into an application and storing profile data in MongoDB. It allows
you to view summary information, profile data, callgraphs and compare runs with
historical data.