New class almost exclusively for creating database connections.

Also has methods for restoring and backing up database, since this is the
only class with access to conenction information.
New class for creating and managing database connections.

Using this class shares a few standard methods and prevents duplicating connections.
_pdo now extends pdo_resources

Allow pdo_resources to manage connection. Inherit escape(), quote(),
restore(), & backup() methods from pdo_resources.

__construct() only calls parent::__construct().
Class (exending pdo_resources) solely for prepared statements.

Limited methods here. Class exists to be constructed multiple times, allowing to cheaply
work with multiple prepared statements.
Merge branch 'import' into dev