Deprecated most of scala.Console.

After realizing the Predef deprecations didn't go nearly
far enough.

See SI-4793 for part of why the set{Out,Err,In} methods
are ill-advised.

Farmed the potentially reusable bits of Console into traits
so they can actually be reused.
Added java.lang.CharSequence to Any-parented traits.

This enables the Seq and Array wrapper classes for Strings to
extends AnyVal and CharSequence simultaneously.
New starr to give CharSequence an Any parent.
Remove deprecated 'exit' from Predef.

And the test updates to match.

Failed to remove 'error' due to its use by sbt. At least all
calls to it from within this repo are now eliminated.
More implicit value classes in Predef.

All of these are now implicit value classes:

  ArrowAssoc, Ensuring, StringFormat, StringAdd,
  RichException, SeqCharSequence, ArrayCharSequence

Non-implicit deprecated stubs prop up the names of the
formerly converting methods.

Segregated deprecated elements in Predef from the part
which still thrives.
Bump sbt.latest.version to 0.12.2.