redmine data reduction: sort per-sprint output by version ID

Signed-off-by: markkampe <mark.kampe@inktank.com>
redmine data reduction - extract/plot issue sources

	new data reduction script (sourcemunch.pl) to break down issues
	by type and source for each reporting period

	new plotting script (sources.plot) to plot this information

	update index.html to display the new information

Signed-off-by: markkampe <mark.kampe@inktank.com>
redmine - factor out a common data reduction script

	new script buggraphs.sh does all of the standard data reduction
	update bugplot.sh to be able to front-end all standard plots
               (required because gnuplot scripts get no command line args)
	remove forcing of input and output filenames in age.plot

Signed-off-by: markkampe <mark.kampe@inktank.com>
redmine data reduction - support relative start/end dates

	It is typical to want to plot N months of history rather
	than the history since x/y/z (because two many entries
	make the graphs unreadable), so I added support for start
	and end dates, relative to the present, in days, weeks,
	months, or years.

Signed-off-by: markkampe <mark.kampe@inktank.com>