Do background of Behat tests in database

Instead of running the background portions of Behat tests in the
browser directly manipulate the database.  This will result in way less
overhead for each test and less chance for failure in a non-test
background segment.
Fix CI db credentials
Don't always instantiate database

The FeatureContext class gets created for every feature and scenario.
Many of these do not need access to the database.
Used a static property to hold a connection so we don’t have to create
it new for every scenario.
More effective PDO resource management

The static connection was hitting packet limits.  Also attempting to
use a persistent connection made the transactions fail.  So instead we
eat the overhead of creating new connections so the tests run.
Merge pull request #621 from jrjohnson/fasterbackground

Do background of Behat tests in database
correct minor typos in comments
Merge pull request #622 from Trott/typos

Even though it failed the build, I'm pretty sure this is safe to merge!
Re-enable IE9 sauce tests
Add ldap error string to exceptions

So it is more obvious what the error is, add the message to the exception message.
Put the ldap error number in the exception message

Instead of just using the string use the ldap error number as well since some ldap string refer to more than one error.
Merge pull request #623 from jrjohnson/ldaperrormessage

Add ldap error string to exceptions
Timeout LDAP connection after 2 minutes

When the ldap connection sits open it gets stale when there are no
searches.  In order to avoid this we need to reset it if it hasn’t been
used recently.  Two minutes seems like a reasonable delay.
Configure local sauce tests

Provide configuration and documentation for running sauce tests against
a local ilios install.
Activate windows 8 IE 11 sauce tests in travis
Activate OSX safari and chrome tests
Reorder travis matrix for sauce

Since sauce limits us to 3 windows and 3 mac VMs it makes sense to
alternate the travis matrix.
Merge pull request #624 from jrjohnson/usersync

Timeout LDAP connection after 2 minutes
Merge pull request #625 from jrjohnson/iesauce

Sauce and Travis improvements