GitLab

* added clang test

* hotfix

* downgrade required AppleCLang version

* fixed CMakeLists

* prevent case when CMake is downgraded by libomp

* fixed Clang test

* moved MSVC version check to the better place

* compile with Clang at Travis on Linux

* clear .travis.yml

* fixed indents

* added support of MPI test at Travis with macOS

* added FAQ entry about OpenMP library error

* updated installation guide

* moved APPLE_OUTPUT_DYLIB to other options

* fix check-docs test: ignore old url from error message

* added example of symlink command in FAQ

* fixed markdown

* capitalized heading

* updated Python installation guide

* changed mode in message command

* added notes about MinGW efficiency problems

* updated R-package installation guide

* use quotes for gcc version

* removed excess 'Note' phrase