customer table resultset to JSON to session

Added code to select the entire customer table (just over 1 MB), convert
it to a JSON array, and store it in session on the first user page view.

Still needs some refinement and possibly an intermediate server-side
data structure, but this should be a good first step toward getting the
front-end started with knockout.js.

Still need to do the same with the transaction table, as well, and
likely separate select statements from database and ssh connection code.