replace subdirs with add_subdirectory (#60)

Reformat using clang-format-5

Merge pull request #58 from petabi/modern-cmake

Update CPACK_SOURCE_IGNORE_FILES

Set PROJECT_VERSION and LANGUAGE for cmake

Remove OS-dependent cmake codes

Let cmake figure out the compiler option for C++14

Bump version to 0.2.2

exit if required library/file is not found (#57)

Merge pull request #56 from petabi/fix-warnings

Use EngineType::rematch only when rematch is used

Fix compiler warnings

Apply Apache License 2.0

Let git ignore VS code directories

Merge pull request #55 from petabi/build_without_pcre2