SI-6807 Deprecating the Actors library.

All public classes, traits and objects marked as deprecated.
Added deprecation note on the package object.
Embedded external libraries (ThreadPool etc.) are not deprecated as they are intended for internal use only.

Review by: @phaller
SI-7091 Add a diagnostic for the "no acc def buf" error.
SI-7091 Don't try to put a protected accessor in a package.

This shows up when a protected[pack] class has a constructor
with a default argument.

Regressed in f708b87 / SI-2296.
Fix typing idempotency bug with Annotated trees

typedAnnotated transforms an Annotated tree into a Typed tree. The
original field of the result is set to the Annotated tree.

The bug was that typedAnnotated was using the untyped Annotated tree
as original, but also set its type. When re-typing later on the same
Annotated tree, the typer would consider it as alreadyTyped. This
is incorrect, the typer needs to convert Annotated trees to Typed.

Also, the Annotated tree only had its type field set, but its children
were still untyped. This crashed the compiler lateron, non-typed trees
would get out of the typing phase.
Merge pull request #2115 from retronym/ticket/7091

SI-7091 Don't try to put a protected accessor in a package.
SI-6642 Code cleanup on RedBlackTree#TreeIterator

In anticipation of some work needed to implement iteratorFrom, this
commit does some variable renaming and general code clean up on
RedBlackTree's TreeIterator.
SI-6642 Adds iteratorFrom, keysIteratorFrom, and valuesIteratorFrom

Adds the ability to efficiently create an iterator that starts at a
given key or element of a sorted set or map. Similar work is done for
key and value only iterators on maps.

The bulk of the work is in RedBlackTree. Most of the rest is pushing
the new api methods throughout the appropriate spots in the collection
API.

This commit leaves undone some similar work possible on mutable TreeSets
SI-6642 Refactor mutable.TreeSet to use RedBlackTree instead of AVL

There was no reason to have mutable.TreeSet use AVLTree while
immutable.TreeSet and immutable.HashSet used RedBlackTree. In
particular that would have meant duplicating the iteratorFrom logic
unnecessarily. So this commit refactors mutable.TreeSet to use
RedBlackTree for everything, including iteratorFrom. It also adds
a test to make sure TreeSet works as expected.

AVLTree should be dead code since it's private[scala.collection.mutable]
and only used by mutable.TreeSet, but to be safe it's only deprecated
in this commit.
SI-6642 Code cleanup from review of iteratorFrom

This commit is code cleanup from the review on
https://github.com/scala/scala/pull/2119

* Changes several instances of
    def f[A, ]… to
    def f[A]…
* Changes several instances of
    def f[A](…)(implicit ordering : Ordering[A])… to
    def f[A: Ordering](…)…
* Changes one instance of
    x == null to
    x eq null
* Changes two instances of
    id + bottomid to
    bottomid + id
Fix SI-7130: Memory leaked caused by Statistics

As described in the ticket, we were leaking memory by holding reference
to Global through by-name argument that was captured by an instance of
a class stored in global HashMap `qs`.

The fix is simple: do not register quantities in HashMap unless statistics
is enabled. This way, if Statistics is disabled we do not store any
references.

We still leak memory in case of statistics being enabled.
SI-7134: don't require doc.Settings in base api of scaladoc.
make Future scaladoc examples up-to-date and compilable
SI-5744 evidence params are now SYNTHETIC

The macro def <-> macro impl correspondence check compares names of the
corresponding parameters in def and impl and reports an error if they
don't match. This was originally designed to avoid confusion w.r.t named
arguments (which ended up being never implemented as described in SI-5920).

Sometimes parameter names are generated by the compiler, which puts the
user in a tough position. Luckily, there's an escape hatch built it, which
omits the name correspondence check if one of the parameters is SYNTHETIC.
Everything went well until we realized that evidences generated by
context bounds aren't SYNTHETIC, which led to the bug at hand.

Marking auto-generated evidence parameters SYNTHETIC was only the first
step, as the correspondence checker uses parameter symbols, not parameter
trees. Why's that a problem? Because SYNTHETIC doesn't get propagated from def
trees to their underlying symbols (see ValueParameterFlags).

Unfortunately one cannot just change ValueParameterFlags, because that
would break printouts generated in TypeDiagnostics, which is designed to not
print synthetic symbols. Thus we modify methodTypeErrorString in
TypeDiagnostics to always print synthetic symbols.

Therefore now we propagate all paramSym.flags when doing correspondent sweeps
to keep them in sync between def trees and their underlying symbols. This
fixes the problem.
Merge pull request #2132 from u-abramchuk/SI5744

SI-5744 evidence params are now SYNTHETIC
Removing disabled, unneeded futures tests
Additional test case for Lukas' fix to annotated originals.

This was inspired by the regression that Mark encountered
when upgrading SBT from 2.10.0 to 2.10.1-RC1.
Merge pull request #1 from retronym/topic/annotatedRetyping-test

Additional test case for Lukas' fix to annotated originals.
unit test ide-t1000567 exercises SI-5063, aka #1000567.
SI-7143 Fix scanner docComment: docBuffer and docPos are initialized
in different places and as a result can get out of sync and as a result
the invariant that docComment has a position is broken.
Merge pull request #2131 from jozic/scaladoc-cleanup

make Future scaladoc examples up-to-date and compilable