Ability to Download Full DB and Query Locally

[lukesonnet]

Because the download can be quite slow, it might be useful to build methods that can hit a local copy of the full db that can be downloaded using a method within the package. Some problems here include:

• ensuring no one overloads the server with download requests
• whether existing functions (search and download) can be easily modified to draw from the local DB or whether they need to be dispatch functions that simply call either the local search or the search on the server
• how to ensure that they have the newest version (presumably some users with local DBs anticipate being offline, and thus it may be hard to check whether they have the latest DB).