Yaramod

* Turned `ImportFeatures` into `Features` because it now affects more than just imported modules ([148](https://github.com/avast/yaramod/pull/148))
* Added support for `of` expression with user-defined arrays ([148](https://github.com/avast/yaramod/pull/148))
* Added support for user-defined variables inside rules scope ([148](https://github.com/avast/yaramod/pull/148))

* Added building of Python wheel for Windows using Python 3.9

* Yara 4.0 features as Base64 string modifier, for loop over dictionary and more ([144](https://github.com/avast/yaramod/pull/144))

* Added new VirusTotal AV external variables

* Converted `TokenType` enum to c++11 enum class ([123](https://github.com/avast/yaramod/pull/123))
* Fixed include directive not to extract tokens ([129](https://github.com/avast/yaramod/pull/129))

* Fixed token location computing of plain and hex strings ([124](https://github.com/avast/yaramod/pull/124))
* Exposed token and symbol file position via python bindings ([120](https://github.com/avast/yaramod/pull/120))
* Fixed both python and c++ bool Simplifiers ([121](https://github.com/avast/yaramod/pull/121))
* Renamed `ModifyingVisitor::cleanUpTokenStreams` to `ModifyingVisitor::cleanup_tokenstreams` ([121](https://github.com/avast/yaramod/pull/121))
* Unified duplicated `location.h` headers ([118](https://github.com/avast/yaramod/pull/118))