Deprecator Exterminator: Systematic de-warningification of Lift 3

I'm going through project-by-project and blowing away warnings, including deprecation
warnings and feature warnings (though currently we don't have `-feature` enabled on
our builds—I've got it turned on locally).

I'm starting out with the main sources and then will go back and clean up test sources.

src:
 - [x] lift-actor
 - [x] lift-common
 - [x] lift-db
 - [x] lift-json
 - [x] lift-json-ext
 - [x] lift-json-scalaz
 - [x] lift-json-scalaz7
 - [x] lift-mapper
 - [x] lift-markdown
 - [x] lift-mongodb
 - [x] lift-mongodb-record
 - [x] lift-proto
 - [x] lift-record
 - [x] lift-squeryl-record
 - [x] lift-testkit
 - [x] lift-util
 - [x] lift-webkit

test:
 - [x] lift-actor
 - [x] lift-common
 - [x] lift-db
 - [x] lift-json
 - [x] lift-json-ext
 - [x] lift-json-scalaz
 - [x] lift-json-scalaz7
 - [x] lift-mapper
 - [x] lift-markdown
 - [x] lift-mongodb
 - [x] lift-mongodb-record
 - [x] lift-proto
 - [x] lift-record
 - [x] lift-squeryl-record
 - [x] lift-testkit
 - [x] lift-util
 - [x] lift-webkit

It's a lot of work for one person, so if you want to jump in, please just let me know
where you want to work. In particular, my familiarity with the db things in Lift (record,
mapper, etc) and with scalaz is significantly lower than other parts of the codebase,
so if someone wants to jump in there, that would be sweet.

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Two steps left:
 - [x] Remove deprecated stuff inside Lift except for binding stuff.
 - [x] Remove deprecated binding stuff.

After all of this, I'll probably deprecate all `BindHelpers` stuff in 2.6 and work through
removing it from Lift 3.