Disable interrupts during code instrumentation

Code instrumentation needs to see a consistent snapshot of a source file. To achieve that we disable interrupts during getInstrumented.
Adds method askForResponse

Adds method askForResponse which returns a response immediately instead of waiting for a result. That way, one can wait for an ask's result using a timeout.
Raw string interpolator

Adds a raw string interpolator raw"..." which does not do any escape sequence processing.
New Worksheet mixing scheme

Debug changes
Merge pull request #1004 from paulp/topic/warnings-2.10.x

Topic/warnings 2.10.x
Merge 2.10.x

Conflicts:
	src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
	src/compiler/scala/tools/nsc/transform/SpecializeTypes.scala
	src/compiler/scala/tools/nsc/typechecker/Infer.scala
	test/files/neg/unchecked2.check
SI-4023 Testcase closes issue with inner classes/getDeclaredClasses
Closed 6029 ...

... in a less nice way than I would like. Essentially, we mask type errors at later stages that arise from comparing existentials and skolems because we know that they are not tracked correctly through all tree transformations. Never mind that all these types are going erased anyway shortly afterwards. It does not smell nice. But as I write in the comment, maybe the best way out is to
avoid skolems altogether. Such a change by far exceeds the scope of this pull request however.
Closes SI-5882

I have added a restriction that value classes may not contain inner classes or objects. This makes sense as the "outer" field of any such classes or objects would be ephemeral, with surprising results. SIP-15 has been changed accordingly.
Merge pull request #1010 from odersky/ticket/6029

Closed SI-6029 ...
Promote unchecked warnings into being emitted by default.

To make that viable, suppression of unchecked warnings is now available
on a per-type-argument basis. The @unchecked annotation has hereby been
generalized beyond exhaustiveness to mean context-dependent "disable further
compiler checking on this entity." Example of new usage:

  def f(x: Any) = x match {
    case xs: List[String @unchecked] => xs.head   // no warning
    case xs: List[Int]               => xs.head   // unchecked warning
  }

It turns out -unchecked has been put to other noisy uses such as
the pattern matcher complaining about its budget like a careworn spouse.
This actually simplified the path forward: I left -unchecked in place
for that and general compatibility, so those warnings can be enabled
as before with -unchecked. The erasure warnings I turned into regular
warnings, subject to suppression by @unchecked.

Review by @odersky.
Merge pull request #968 from paulp/topic/remove-core-classes-first

Removed "core classes first" logic.
Merge pull request #991 from adriaanm/ticket-5958

SI-5958 This deserves a stable type
Merge pull request #1006 from adriaanm/master

merge 2.10.x into master
Merge pull request #1002 from magarciaEPFL/fixes210

SI-6142: warn @inline-methods ending up not inlined (rightfully or not)
Closes SI-5878

We need to impose an additional rule on value classes: They may not unbox directly or indirectly to themselves.
Merge pull request #988 from paulp/issue/4560

Issue/4560
Merge pull request #990 from VladUreche/issue/6140

SI-6140 Scaladoc infinite recursion in wiki parser
Merge pull request #992 from paulp/topic/list-inlining

Optimization in List.
Merge pull request #996 from gkossakowski/instrumentation-fixes

Partest instrumentation fixes