[cfe-dev] Updating LICENSE.TXT files

[Robinson, Paul via cfe-dev]

In prepping our next release, we noticed that the LICENSE.TXT files
were still all copyrighted 2015.  I've done a bit of archaeology and
it looks like the files to update are:

cfe/trunk/LICENSE.TXT
clang-tools-extra/trunk/LICENSE.TXT
compiler-rt/trunk/LICENSE.TXT
libclc/trunk/LICENSE.TXT
libcxx/trunk/LICENSE.TXT
libcxxabi/trunk/LICENSE.TXT
lld/trunk/LICENSE.TXT
llvm/trunk/LICENSE.TXT
polly/trunk/LICENSE.TXT
polly/trunk/tools/GPURuntime/LICENSE.TXT

Also over time the various conf.py scripts have been modified to
interpolate the current year instead of hard-coding it; I see two
left that do not have this change:

clang/docs/analyzer/conf.py
lld/docs/conf.py

I'm willing to do the grunt work if somebody else is willing to
agree that this is the list of files that need updating.
Thanks,
--paulr