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.
Allow nested calls to `askForResponse` in the presentation compiler.

Fix #6312.

review by @odersky,@lrytz.
Fixes typos in the ScalaDoc of StringContext
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.
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).
Removing duplication from Duration.

I don't know what good it is to have code review if we are checking
in code like this. We must raise the bar, people. When the
justification for code being in the standard library is borderline
at best - as it is here - then the code must be of exceptional
quality. This code is not of exceptional quality.

Mostly these are not behavioral changes, but:

 - I removed finite_? as it is a gratuitous deviation from
   every isXXX method in the world.  This isn't ruby.
 - I removed all the regexps, which only made things complicated
 - I removed all the unnecessary casts, which is to say, all of them
 - I made more things final, sealed, and private
 - The unapply structure was all wrong; returning Option[Duration]
   on the string unapply meant you'd have to say
     case Duration(Duration(x, y)) => ...
   So I fixed apply and unapply to be symmetric.
 - And I removed the "parse" method, since it was doing what
   apply is supposed to do.

There's a test case to exercise accessing it from java,
which also reveals what I hope are bugs.

Thanks to viktor klang for DurationConversions.
Sort files to see if we get reproducible testing results across linux/mac
More fix for invalid companions.

Eliminated InvalidCompanions exception entirely.  Anyone's
guess why we unholstered this exception every time someone
calls "isCodefinedWith" rather than when symbols are created.
I moved the check into Namers, where it can be done once and
with sufficient finesse not to crash so much.

With this patch in place, "playbench" can be built with java7.
removes Type.isConcrete

This method was no longer used anywhere, except for a place where it wasn't
really necessary.

Its implementation is non-trivial, and I have doubts about it, so I propose
to remove it altogether instead of living with some dubious code necessary
for some dubious matter.
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
SI-6246 deprecated apis for core class tags

Aliases ClassTag.XXX to Manifest.XXX to reuse already existing
implementations of deprecated APIs.
fixes Manifest.Nothing and Manifest.Null

Also introduces an important change to Manifest.Nothing and Manifest.Null.
Previously their `erasure` was equal to classOf[Object]. Now it's correctly
set to classOf[scala.runtime.Nothing$] and classOf[scala.runtime.Null$]
correspondingly.

See a discussion here:
https://groups.google.com/forum/#!topic/scala-internals/Y0ALGo7QPqE
Fix for SI-6333 - Try throws from combinators.

* Added  more comprehensive tests to Try.
* Delineated what methods do and don't catch exceptions in docs.
* Fixed combinator methods that should catch exceptions.
Minor code style alterations and performance fixes.

Specifically, avoid reinstantiating an immutable object to alter the type parameter *IF*
that type parameter has nothing to do with the contents of the object.