Bugfix Release v1.2.8

Pull request #30, the CMakeLists.txt will automatically exclude building examples and tests when used as submodule, the configuration options now use a prefixed name to
reduce risk of conflicts.
Pull request #24, install target now creates a ghcFilesystemConfig.cmake in ${CMAKE_INSTALL_LIBDIR}/cmake/ghcFilesystem for find_package that
exports a target as ghcFilesystem::ghc_filesystem.
Pull request #31, fixes error: redundant redeclaration of 'constexpr' static data member deprecation warning in C++17 mode.
Pull request #32, fixes old-style-cast warnings.
Pull request #34, fixes TOCTOU situation on fs::create_directories, thanks for the PR!
Feature #35, new CMake option to add an install target GHC_FILESYSTEM_WITH_INSTALL that is defaulted to OFF if ghc::filesystem is used via add_subdirectory.
Bugfix for #33, fixes an issue with fs::path::lexically_normal() that leaves a trailing separator in case of a resulting path ending with .. as last element.
Bugfix for #36, warings on Xcode 11.2 due to unhelpfull references in path element iteration.

Provide feedback