SI-6258 Reject partial funs with undefined param types

This regressed with virtpatmat.

With -Xoldpatmat, pattern matching anonymous functions with
an expected type of PartialFunction[A, B] are translated to
a Function tree, and typed by typedFunction, which issues an
error of the parameter types are not fully defined.

This commit adds the same check to MatchFunTyper.

It doesn't plug the hole in RefChecks#validateVariance (which is
reminiscent of SI-3577.) Seems to me that in general one should handle:
  a) both BoundedWildcardType and WildcardType
     when in a place that can be called during inference, or
  b) neither otherwise
Deprecate unmaintained/old classes for removal in 2.11
Fix SI-6294.
Two fixes for the worksheet instrumenter

(1) Handle empty worksheets
(2) Handle for expressions

Review by @dragos
Removed dead code.
Made instrumenter more robust by looking at tokens

Made instrumenter more robust by taking into account the positions of the tokens in the source. This allows us to reliably put instrumentation code at the end of the previous token, which tends to put it at end of lines. Furthermore, we now skip left parents. Previously, the instrumenter got confused for a statement like

( x + 1 )

because it thought that the statement started at the `x` and not at the `(`.

Another small change is that we now use decoded names in the worksheet. So ??? will show as ??? not $qmark$qmark$qmark.
Removed previosuly uncommented code, added more diagnosis output to REPL.
Allow nested calls to `askForResponse` in the presentation compiler.

Fix #6312.

review by @odersky,@lrytz.
Fixes typos in the ScalaDoc of StringContext
Merge pull request #1192 from jsuereth/deprecate/low-hanging

Deprecate unmaintained/old classes for removal in 2.11
Merge pull request #1217 from axel22/issue/6294

Fix SI-6294.
SI-6274 Fix owners when eta-expanding function with byName param

When eta-expanding a function that takes a by-name param the local definition
for the corresponding argument is a function-0

  val eta$1 = () => { argument-to-by-name }

If there are any definitinos in the `argument-to-by-name`, the symbol
owner needs to be changed to the anonymous function's symbol.

To know the function symbol in eta expand, we need to type-check the
function, and therefore pass the `Typer` instance to `etaExpand`.
Fixes SI-6285 - ParIterableLike no longer says sequential foreach.
Merge pull request #1246 from lrytz/t6274

SI-6274 Fix owners when eta-expanding function with byName param
Merge pull request #1248 from jsuereth/fix/SI-6285

Fixes SI-6285 - ParIterableLike no longer says sequential foreach.
Merge pull request #1245 from dragos/issue/fix-6312

Allow nested calls to `askForResponse` in the presentation compiler.
Merge pull request #1244 from dgruntz/2.10.x

Fixes typos in the ScalaDoc of StringContext
Fixed positions in de-aliased special symbols and for automatically added `apply` methods.

Fixed #5064, thanks to @paulp who showed the right direction (and how to test it).
Merge pull request #1219 from odersky/topic/worksheet-instrumenter

More worksheet nstrumentation changes
Merge pull request #1251 from dragos/issue/fix-5064

Fixed positions in de-aliased special symbols..