Add Docker dockerfiles for building the parser

The centos6 version should be able to train models but should get modified to use Docker data volumes for dealing with the corpus. 

See my blog for a tutorial on using the Python parsing shell GUI.
http://jimwhite.github.io/blog/2014/10/28/bllip-parsingshell/

An alternative to putting the dockerfiles in this repo is having separate repos but this seems like the simple thing to do.