Merge 2.10.x into master

- 78d15a1308: git merge 5d54cf9e37 -m"Merge 2.10.x into master. [...]"
- 21fc4c710f: git merge c4eede47d7 2cf6c5d7e5 387fbf459e [1]
- a941850c2e: git merge 1a84c86ce4 -m"Merge 2.10.x into master."
- 6dda983596: git merge 773f6a8df9 -m"Merge 2.10.x into master."
- c46f5ba694: git merge -s ours scala/2.10.x -m"No-op merge for [nomaster] part of 2.10.x"

The last merge was indeed ok to be no-op:

```
$ git log 6dda983596..scala/2.10.x --oneline --stat:
1176035f27 (scala/2.10.x) Merge pull request #2193 from adriaanm/patmat-refactor
f482d5bdd0 (scala/pr/2193) Merge 2.10.1 into 2.10.x
33e32179fd (tag: v2.10.1-RC3, scala/2.10.1) Merge pull request #2190 from adriaanm/test-runs-mima-2.10.1
54a9f1bb76 Merge pull request #2189 from adriaanm/ticket-7195
09130d55fd (scala/pr/2189) [nomaster] SI-7195 minor version mustn't introduce warnings
 src/compiler/scala/tools/nsc/typechecker/Typers.scala |  4 +++-
 test/files/neg/t5954.check                            | 16 ----------------
 test/files/neg/t5954.flags                            |  1 -
 test/files/neg/t5954.scala                            | 46 ----------------------------------------------
 4 files changed, 3 insertions(+), 64 deletions(-)
b775d8f16d (scala/pr/2190, adriaanm/test-runs-mima-2.10.1, test-runs-mima-2.10.1) test.done again checks bin compat (using mima 0.1.5)
 bincompat-backward.whitelist.conf | 4 ++++
 build.xml                         | 8 ++++----
 2 files changed, 8 insertions(+), 4 deletions(-)
440bf0a8c2 (2.10.1) Merge pull request #2168 from retronym/ticket/7183
0303e64efa (scala/pr/2168) SI-7183 Disable unreachability for withFilter matches.
 src/compiler/scala/tools/nsc/typechecker/PatternMatching.scala | 42 ++++++++++++++++++++++++++++--------------
 test/files/pos/t7183.flags                                     |  1 +
 test/files/pos/t7183.scala                                     | 13 +++++++++++++
 3 files changed, 42 insertions(+), 14 deletions(-)
```

[1] determined all commits in HEAD..scala/2.10.x that merged cleanly as follows:

```bash
commits=$(for c in `git rev-list 78d15a1308..scala/2.10.x`; do if ( git merge -n $c &> /dev/null ); then echo "OK: $c" && grh HEAD^; else grh; fi; done | grep OK: | perl -pe 's/OK: //')
git merge $commits -m"Merge 2.10.x into master."
```

review by @gkossakowski, @paulp