add README and LICENSE for run-clang-tidy.py

This should give more proper attribution to the script origin.

See discussion:
- #443

.travis.yml

@@ -46,7 +46,7 @@ matrix:
         - make -k
         - make check
         - |
-          ../server/run-clang-tidy.py \
+          ../server/build-aux/run-clang-tidy/run-clang-tidy.py \
           -clang-tidy-binary clang-tidy-4.0 \
           -clang-apply-replacements-binary clang-apply-replacements-4.0 \
           -p . \

server/build-aux/run-clang-tidy/LICENSE.TXT

@@ -0,0 +1,43 @@
+==============================================================================
+LLVM Release License
+==============================================================================
+University of Illinois/NCSA
+Open Source License
+
+Copyright (c) 2007-2016 University of Illinois at Urbana-Champaign.
+All rights reserved.
+
+Developed by:
+
+    LLVM Team
+
+    University of Illinois at Urbana-Champaign
+
+    http://llvm.org
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal with
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+    * Redistributions of source code must retain the above copyright notice,
+      this list of conditions and the following disclaimers.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimers in the
+      documentation and/or other materials provided with the distribution.
+
+    * Neither the names of the LLVM Team, University of Illinois at
+      Urbana-Champaign, nor the names of its contributors may be used to
+      endorse or promote products derived from this Software without specific
+      prior written permission.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
+SOFTWARE.

server/build-aux/run-clang-tidy/README

@@ -0,0 +1,12 @@
+Origin:
+- http://llvm.org/svn/llvm-project/clang-tools-extra/trunk/clang-tidy/tool/run-clang-tidy.py?p=294607
+- https://github.com/llvm-mirror/clang-tools-extra/blob/c2e903ec98385b82e35bdb303e411854a2e8c032/clang-tidy/tool/run-clang-tidy.py
+
+Modifications:
+- the python version has been frozen to python2,
+  as the script is not python3-compatible
+- added -warnings-as-errors option
+- the run-clang-tidy.py script has been modified
+  to return a sensible exit code when running on Travis CI,
+  i.e. it honors exit code of the underlying processes
+  causing build failures on pull requests