SI-6955 switch emission no longer foiled by type alias

dealiasWiden the type of the scrutinee before checking it's switchable
now with tests! (using IcodeTest since javap is not available everywhere)

rebase of #1879
SI-6964 Remove build managers, both simple and refined.

Deprecated in 2.10.0, out to pasture in 2.11.0.

Users are advised to migrate to:

   https://github.com/typesafehub/zinc
   http://www.scala-sbt.org/
Cleaned up meta-annotations.

There were some missing and some others not added to the
set of meta-annotations. I added the missing ones and
defined the set in such a way as to include them all, even
those which have not yet been born.
SI-6375, warn on lost annotation.

Annotations on abstract vals which are not meta-annotated
were silently discarded. Still discarded, only less silently.
I warned on as many "lost annotation" situations as I was
reasonably able to cover without false positives.
SI-5189 detect unsoundness when inferring type of match

GADT skolems encode type slack that results from pattern matching on variant type constructors
I thought they would not longer be relevant after cases have been typed,
and since they caused weird issues with the old pattern matcher, I deskolemized in typedCase

however, when we don't have an expected type for the match, we need to keep the skolems around
until the skolemized type makes it out of the match and it becomes the result of type inference for that match
when you do have an expected type, it will propagate to the case-level and the confrontation will thus
already take place when typing individual cases
remove hack for old patmat unnecessary in 2.11
Tweaked meta-annotation error based on feedback.
Merge pull request #1877 from adriaanm/rebase-1876-master

SI-5189 detect unsoundness when inferring type of match
Merge pull request #1803 from paulp/issue/6375

SI-6375, warn on lost annotation.
Merge pull request #1897 from retronym/ticket/6964

SI-6964 Remove build managers, both simple and refined.
Merge pull request #1881 from adriaanm/rebase-1879-master

SI-6955 switch emission no longer foiled by type alias