Lg-cpplint

-----

* Fix 83, output formats "sed" and "gsed" to auto-fix some issues
* Fix 92, new category "build/namespaces_headers" for unnamed namespaces in header file
* Sort list of files before processing
* Fix 144 Falso positive for indent when using QT macros "signals" and "slots"
* Fix 76 Parsing of class decorators that also use digits
* Fix 139 Add message "Relative paths like . and .. are not allowed"

-----

* Revert 43 behavior change for include order from 1.5.0, and hide it behind command-line-flag `--includeorder=standardcfirst`.
It turns out there is no easy objective way to tell c system headers from certain c++ library headers, and Google cpplint intentionally classifies some C++ header includes as C system header for simplicity.
* Libraries considered as C system headers using --includeorder=standardcfirst now also includes linux-specifc headers (glibc-devel, glibc-kernheaders, linux-libc-dev).

-----

* Fix 43 false positives in header include order by checking includes against a list of c headers.
Since this interprets certain include lines different than before, output about header include order changes.

-----

* Fix 135: allow 'if constexpr' in readability/braces.
* Fix runtime warning: Close files after reading contents

-----

* Avoid false positive for [build/include_what_you_use] in case of `foo.set<type>` and `foo->set<type>` usage.
* Avoid false positive for [build/include_what_you_use] in case of `map` is user defined function
* Escape backslashes in pydoc strings to get rid of DeprecationWarning.
* Fix false positive "should include its header" for 3rd party headers
* Add support for c++17 tuple destructuring
* fix 123: Inconsistent behavior of --headers and --extensions
* Fix 114: --exclude not working recursively
* fix 112, identifying of copy constructors should allow combinations of volatile and const

-----

Another cleanup release

* NOBUG: fix unit/cli tests for source release
* NOBUG: reduce diff to upstream by intentionally using deprecated functions where upstream uses them
* add `--version` command (https://github.com/cpplint/cpplint/issues/27)