Add principal first- and last-name

[Briehan Lombaard]

We need principal first- and last-name fields on the Proposal model:

• add two new fields
• update reference property to use the last name field
• remember to populate the initial values for the new fields on the form when creating a new proposal

[Briehan Lombaard]

Added principal first- and last name. Fixes #5

→ <<cset 68bf152c8dbe>>

[Briehan Lombaard]

Merged in matthiasschulz/observer-portal/principal-names-5 (pull request #16)

Added principal first- and last name. Fixes #5

→ <<cset e274bdc8a75f>>

[Briehan Lombaard]

Forgot to add the two new fields to the initial defaults when adding a new proposal.

[Briehan Lombaard]

Fixed in #574a478