Refactor Action constructor to build its own database descriptor

[magsol]

When an Action constructor is invoked, it should build (from scratch) and maintain its own connection to the database. This will furthermore ensure that child processes do not accidentally inherit the parent's database descriptor.

[magsol]

In reference to Issue #6, have the construction of each Action performed as late in execution as possible, namely when a child process is in control.

[magsol]

This issue is on hold: part of the problem is that the Actions need to be constructed in order to use their getNextAttempt() method to determine when to fire them, but doing so also initializes a database connection (if it's in the constructor) before the child process has been spawned for the Action, thereby creating the problem this ticket was meant to address.

For the time being, the fix is to add the following line to the start of every Action's run() method:

if (!isset($this->db)) { $this->db = Storage::getDatabase(); }

[magsol]

Current milestone will likely not support a fix to this; removing this from the current milestone.

[magsol]

This needs to be refactored in such a way that the database descriptor is only created when the action fires, since the action is assigned a new child process every time it runs. With the descriptor built in the constructor, it would only work once until the second time the action is called and spun off into a child process.