Pull request for branch 'Required proxy sites #473' - also #453 

This also came to encompass #453 - 'Review SSL certificate verification in LanternTrustManager.' One of the major changes in this branch is the use of System property for the global trust store - the call:

System.setProperty("javax.net.ssl.trustStore", TRUSTSTORE_FILE.getAbsolutePath());

On one level, the LanternTrustStore class replaces LanternTrustManager, completely eliminating our manual certificate and certificate chain verification - #453 - and replacing with with our generated trust store with only the certs and signing certs we trust -- three of them primarily for the sites in #453 that we have to call internally. These are the equifax cert for all google sites as well as for query.yahoo.com and the digicert cert for exceptional.io. We finally also trust the littleshoot cert for connecting to LittleProxy.

@aranhoide do you think you could take a look at these changes and integrating them? The goal was to simplify and improve security, but this definitely ended up touching a lot of classes.