Don't hop to the first enclosing, non-silent context when typing refinements.

Closes SI-5305.

This reverts a few lines of e5cfe47a19, which was a remedy for SI-3614 and SI-3856*. I added a test case for the former, the
latter was already tested. Both tests pass after this change, and they do so with the old and new pattern matcher.

But does this change still "avoid trees with null types in presentation compiler"? What was the intent of the context hopping in the first place?

* Based on this comment: https://issues.scala-lang.org/browse/SI-3614?focusedCommentId=50477&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-50477, which elaborates further than the commit comment of e5cfe47a19.
Add more logging.
Fixes SI-5801, error messages regression. Review by @adriaanm
better feedback for SI-5044
Fixes SI-4717.

A lazy val declared inside an anonymous class inside a specialized
context no longer crashes Duplicators.

Previously, a duplicated lazy val was assigned to the wrong owner
in Duplicators:

    def x[B >: A]: Unit = new Bounds[B] {
      lazy val it = ???  // def or val okay
    }

Above, the `it` in `$anon` in `x$mcZ$sp` had its owner set to `x$mcZ$sp`
instead of `$anon`. This crashed the typer when it had to retype its
lazy accessor, because there was no `lazy var it` in `$anon$`.
Furthermore, the duplicated symbol wasn't being added to the list of
declarations of `$anon`.

Changes:
1) `invalidate` in Duplicators takes an additional parameter which is
the new owner of the new symbol that has to be duplicated. If this parameter
is set to `NoSymbol`, then the new owner is `context.owner`, as before.
2) the newly created lazy val symbol is being added to the list of
declarations of its new owner.

Removes debugging output from the previous commit.

Review by dragos.
@mention dragos
Further fixes SI-4717.

Only adding a lazy val into list of declarations if the owner is a class.

Review by dragos.
@mention dragos
Fixes previous commit.

Should be checking if the owner of the new symbol is a class, not the new symbol itself.
Adding the Actor Migration Kit.

  Kit consists of:
    1) The StashingActor which adopts an interface similar to Akka.
    2) Props mockup for creating Akka like code
    3) Pattern mockup
    4) Test cases for every step in the migration.
    5) MigrationSystem which will paired on the Akka side.

  Review of the code : @phaller
  Review of the build: @jsuereth
Added Scaladoc keyboard shortcut: tab toggles between panels
Fixes SI-5804.

The hash table initialSize method is now within
the the hashset and hashmap classes, and not in the companion.
Overriding this method now yields hashmaps and hashsets
of the proper initial capacity.

Review by @phaller.
Fix SI-2488
Minor fix to Tab-switch keyboard shortcut
Merge pull request #568 from hubertp/issue/5801

Fix SI-5801: error messages regression.
Merge pull request #577 from lrytz/wip/t2488

Fix SI-2488: allow named arg, in original position, before positionals
Merge pull request #578 from lrytz/wip/t5044-squashed

fix SI-5044: better error message on cyclic error and named/default args
Fix 4812

Remove default arguments from parameter ValDefs in UnCurry.
Merge pull request #581 from lrytz/t4812-unc

Fix SI-4812: handle trait method with Symbol as default for argument
Adds ability to navigate Scaladoc with arrow keys
Actually fixes SI-5055. Scaladoc now a zillion times less annoying
Merge pull request #582 from heathermiller/scaladoc/keyboard-shortcuts

Fix SI-5055 (for real). Implement keyboard shortcuts in Scaladoc. Browsing is fun again!