showRaw now prints symbols of def trees

A very useful addition that came in handy when hacking macro annotations
[nomaster] macro errors now always have positions

Back then when I implemented macros for inclusion in trunk (Spring 2012),
partest didn't support the _1, _2, ... convention for neg tests, so I had
to use toolboxes to test macro-generated exceptions.

Unfortunately toolboxes aren't very good with positions (mostly because
their inputs are almost always constructed without corresponding sources)
so I didn't notice that errors signalizing about macro-generated
exceptions actually don't carry positions with them because of a typo.

This patch fixes the oversight, but it doesn't need to be ported to master,
because over there everything's already fixed by one of the backports
from macro paradise.
currentRun.compiles now correctly works in toolboxes

Another random bug uncovered and extinguished when hacking macro annots.
Merge pull request #2818 from xeno-by/topic/macro-expansion-error-pos

[nomaster] macro errors now always have positions
Merge pull request #2817 from xeno-by/topic/toolbox-current-run-compiles

currentRun.compiles now correctly works in toolboxes
Merge pull request #2813 from xeno-by/topic/showraw

showRaw now prints symbols of def trees
[nomaster] SI-7733 reflective packages now more consistent with scalac

Previously PackageScopes from scala.reflect ignored all classes that
had $'s in non-rightmost positions in their names.

Unfortunately this behaviour is inconsistent with how scalac does things,
and I reconciled this as usual, by pulling corresponding logic into
scala-reflect.jar and sharing it between runtime reflection and compiler.

This change has seprate pull requests for 2.10.x and 2.11.0. The latter
deprecates `scala.tools.nsc.util.ClassPath.isTraitImplementation`
whereas the former (which you're looking at right now) does not, because
we can't deprecated members in minor releases.
Merge pull request #2809 from xeno-by/ticket/7733

SI-7733 reflective packages now more consistent with scalac