fix for connection pooling.

by defining these methods in the adapter class, we prevent calls from the ConnectionPool class being proxied to the master connection. this allows pool checkouts/checkins to work as expected without interacting with the master/slave connections.
Rails 4 support
Make instructions about errors during startup more explicit.
Hook into rails db:* tasks load_config so seamless_database_pool can remove itself for tasks that are based on the adapter name.
Merge branch 'master' of https://github.com/red5studios/seamless_database_pool into red5studios-master
Merge branch 'rails4' of https://github.com/mobi/seamless_database_pool into mobi-rails4
Update connection adapter specs to use mysql2 gem instead of old mysql gem.
update history and version number
Add class name to dynamically generated connection adapter for compatibility with code that looks at the name.
Regenerate gemspec for version 1.0.13
Merge branch 'master' into our-vendored-patches

Conflicts:
	lib/active_record/connection_adapters/seamless_database_pool_adapter.rb