Replace highcharts with Rickshaw
Working basic graph
Add x-axis and y-axis
Get area charts to work
Remove log statements
Use logarithmic scale on y-axis
Much simpler graph update scheme.

* Using the Rickshaw-provided Rickshaw.Series class, it's much cleaner
  to get the proper rendering and update of graph.
Stacked bar graph, finally
Use a fixed sized window to display graphs

* In other words, now the series data objects behave like a sized queue.
Remove unused filler data generation function

* This is provided by Rickshaw.Series. No need to hand-roll this.
Move libraries, source code to appropriate folders
Remove initial Rickshaw prototype code
Rename working Rickshaw source file
Replace asset path with new scheme
Merge branch 'master' into add-rickshaw
Avoid using global variables, use classes instead
Fix multiple rendering of bars

* Due to setInterval(tryQtBridge, 1000), for every 1 second, a new
  series point gets added to the graph resulting in a increase in the
  number of bars per tick as time passes by.
Extract out rendering axes part
Add rudimentary legend functionality
Add highlighting to legend