Don't crash if cpsParam is not on the classpath.

When checking if a piece of code needs the continuations plugin, the cpsParam classes may not be on the class path. Assume it does not need it in that case.
Don't use the BrowsingLoader for Java sources. 

When the presentation compiler needs a SourceLoader, instead of immediately adding the file 
to the compilation round it uses a fast parser to create symbols for all top-level class definitions. 
The fast parser assumes Scala sources, which is not always the case.
Don't require symbols to be loaded in the parser.

The parser special-cases primitive types. For comparing the name, it relied on having the symbols 
for primitive types already loaded, which is not always the case. The presentation compiler 
may parse sources for, say, scala.Int, and therefore the symbol for Int may not be yet available.
Remove NPE when `compileLate` sees sources during initialization.

When a symbol needed in Definitions is loaded, it may be that the corresponding source is newer than
the classfile. That will send it to `compileLate`, but no phase is yet set. We simply add it to the 
compilation pipeline and continue gracefully.
SI-5617 Better error message for "x overrides nothing".

"It looks like you're trying to override a method", notes Clippy.
SI-4842 Forbid access to in-construction this in self-constructor args

The check was already in place for direct calls to the super constructor.
Without this additional check, ExplicitOuter crashes, as it doesn't create
an $outer pointer for the constructor-arg scoped inner object, but expects
one to exist when transforming the Outer.this reference.
Updated scalacheck sources.

To current scalacheck head 7ffda752d8 except for this diff:

diff -rw src/scalacheck/org/scalacheck/Arbitrary.scala /s/scalacheck/src/main/scala/org/scalacheck/Arbitrary.scala
13d12
< import scala.reflect.ClassTag
281c280
<   implicit def arbArray[T](implicit a: Arbitrary[T], c: ClassTag[T]
---
>   implicit def arbArray[T](implicit a: Arbitrary[T], c: ClassManifest[T]
diff -rw src/scalacheck/org/scalacheck/Prop.scala /s/scalacheck/src/main/scala/org/scalacheck/Prop.scala
63c63
<   def mainCallsExit = false
---
>   def mainCallsExit = true
Only in /s/scalacheck/src/main/scala/org/scalacheck: ScalaCheckFramework.scala
diff -rw src/scalacheck/org/scalacheck/util/Buildable.scala /s/scalacheck/src/main/scala/org/scalacheck/util/Buildable.scala
13d12
< import scala.reflect.ClassTag
34c33
<   implicit def buildableArray[T](implicit cm: ClassTag[T]) =
---
>   implicit def buildableArray[T](implicit cm: ClassManifest[T]) =
Making Actor Migration Tests deterministic.

Review by: @phaller
Merge pull request #711 from dragos/issue/no-crash-missing-cpsParam

Don't crash if cpsParam is not on the classpath.
Merge pull request #731 from retronym/ticket/5617

SI-5617 Better error message for "x overrides nothing".
Merge pull request #735 from retronym/ticket/4842-2

SI-4842 Forbid access to in-construction this in self-constructor args
Merge pull request #748 from jsuereth/update-scalacheck-source

Updated scalacheck sources.
Merge pull request #753 from vjovanov/actor-tests-fix

Making Actor Migration Tests deterministic.
Merge pull request #712 from dragos/issue/hardening-compiling-with-newer-sources

Issue/hardening compiling with newer sources