Add clang-3.5 to ubuntu-precise; resolves travis-ci/apt-package-whitelist#2625
Add clang-3.5 to ubuntu-precise; resolves travis-ci/apt-package-whitelist#2625

Packages: clang-3.5 clang-format-3.5 cpp11-migrate-3.5 clang-modernize-3.5 clang-3.5-doc libclang1-3.5 libclang1-3.5-dbg libclang-3.5-dev libclang-common-3.5-dev python-clang-3.5 clang-3.5-examples libllvm3.5v5 libllvm3.5-dbg llvm-3.5 llvm-3.5-runtime llvm-3.5-dev llvm-3.5-tools libllvm-3.5-ocaml-dev llvm-3.5-doc llvm-3.5-examples lldb-3.5 liblldb-3.5 python-lldb-3.5 liblldb-3.5-dev lldb-3.5-dev

travis-ci/apt-package-whitelist,travis-ci/apt-package-whitelist