Adding PdoSessionHandler from Symfony project
Add PdoSessionHandler to lib includes
Add pre-install configuration and installation of sessions database
Add sessions.db to git ignore
Register database session handler, when DSN is configured
Wrap text in license file
Removed separate sessions database configuration, added option to store sessions in primary database
Added session tables to create_tables scripts
Added support for USE_DATABASE_SESSIONS option
Updated setup_database script to work for mysql
Removed sessions.db from gitignore
Updated reference statements to be compatible with mysql
Merge pull request #96 from jmfee-usgs/GMP-370

Gmp 370