Ability to flatten benchmark and observation data.

This is for #54; benchmark and observation data are complex
dictionaries. esbench.analyze.flat() function will combine benchmark and
observation data for each observation, and flatten the data into a list
of (name, value) tuples, where name is built by combining all the
dictionary key names leaving to the value, joining keys with periods. If
there are lists, element indexes are inserted, so you may end up with a
tuple like: ('foo.bar.1.x', 'baz'). flat() also takes a list of regex
strings which will be used to filter the resulting key strings.
Closes #55, remove 'svg' from 'show' options.
Work in progress.
Work in progress.

Checking in before trying new way of implementing analyze.filter_tuples
(using just a single extended regex).
Work in progress, getting there, lunch time.
Progress on csv output, also piping into gnuplot.

Running 'esbench show -h' will now display information on how to do
'post processing' on the csv data, including info on how to send it to
gnuplot for graphing. I AM VERY EXCITED ASBOUT THAT!