BTMash's sandbox: Signup Registration migration

This is the preliminary home of the signup to entity registration migration module. This will copy over all signups from the prior signup module tables over to an entity named 'signup_entity_migration' (first step; maybe make it more flexible down the line).

UPDATE AS OF Feb 3, 2011:

• When the module is installed, it will automatically create an registration bundle named signup_registration. This is for an easier migration process.
• It currently creates a field named signup_registration_name to go with it. I have not yet decided what should happen to the phone number. It is fairly easy to implement, however.
• The registration bundle field is attached to all prior nodes that had signup enabled on them. I haven't started to look at setting up any other information regarding this.
• The module will use the migrate module for migrating over prior nodes and signups. Most of the node settings migrate over. However, there are a few things that need to get sorted out such as how to get the prior node date in as the closing date. I'm not sure how field names change between D6 and D7 (cck to core fields) so moving over the dates may be a bit of a challenge. But aside from that, all other data is migrating over fairly nicely.
• The signup log is migrating over very well. The destination handler is very flexible and will handle pretty much anything that gets thrown at it so its all up to the actual migration implementation at this stage. As mentioned above, the phone field is not captured. I haven't looked at contrib at all so far so that may be another challenge.

Please note that all issue activity will take place in #1412254: Migration plan from signup to entity registration?. It is attached to registration for better exposure as that is the main module.