Reworked intro with new citations, closes #36

- new bib file (includes some refs I have yet to cite, but maybe should)
- Different intro flavor in light of lack of gait data.
I prefer editing the master branch directly on github.com.  I already 
started doing that and I think this is OK because I only touch the 
content (not the formatting) in paper.tex.  Can we do it that way?

Still not quite comfortable with the git process.

Ton

On 12/11/2014 5:47 PM, Jason K. Moore wrote:
>
> In paper.tex 
> <https://github.com/csu-hmc/perturbed-data-paper/pull/54#discussion-diff-21716539>:
>
> > -reactions and motion of an able-bodied person. A modern gait lab is able to
> > -collect a variety of kinematic, kinetic, and physiological data from humans
> > -during gait. This data can potentially be used to drive the design of the human
> > -mimicking controller. With a rich enough data set, one may be able to identify
> > -control mechanism used during a human's natural gait and recovery from
> > -perturbations. We have collected data that we believe is richer than previous
> > -gait data sets and may be rich enough for control identification. The data can
> > -also be used for verification purposes for controllers that have been designed
> > -in other manners.
> > -
> > -We collected over five and half hours of perturbed gait data from 15 subjects
> > -sampled at 100 hz. The data has been organized and made available for other
> > -research uses.
> > -
> > -\section*{Particpants}
> > +The collection of dynamical data during human walking has a long history
>
> This is an example line comment. You can make them too or I can merge 
> this and then you edit from the master branch. What do you prefer?
>
> —
> Reply to this email directly or view it on GitHub 
> <https://github.com/csu-hmc/perturbed-data-paper/pull/54/files#r21716539>.
>