Add full name to account and use it to create commits (#125)

The Git practice is to use the full name when creating commits, not a
user name. This commit fixes that by introducing a fullName field to
Account and using it when creating commits.

For migrating from earlier versions, the user name is used as an initial
value for the full name field.
Merge branch 'account-full-name' of https://github.com/robinst/gitbucket into robinst-account-full-name

Conflicts:
	src/main/scala/app/PullRequestsController.scala
(refs #127)Display full name at the account page.