Port changes from release-0.2 branch (#87)

* Add CHANGELOG.md (#85)

CHANGELOG.md

+# Changelog
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+### Added
+- New annotation shapes: polygons, polylines, points
+- Undo/redo feature
+- Grid to estimate size of objects
+- Context menu for shapes
+- A converter to PASCAL VOC format
+- A converter to MS COCO format
+- A converter to mask format
+- License header for most of all files
+- .gitattribute to avoid problems with bash scripts inside a container
+- CHANGELOG.md itself
+- Drawing size of a bounding box during resize
+- Color by instance, group, label
+- Group objects
+- Object propagation on next frames
+- Full screen view
+
+### Changed
+- Documentation, screencasts, the primary screenshot
+- Content-type for save_job request is application/json
+
+### Fixed
+- Player navigation if the browser's window is scrolled
+- Filter doesn't support dash (-)
+- Several memory leaks
+- Inconsistent extensions between filenames in an annotation file and real filenames
+
+## [0.1.2] - 2018-08-07
+### Added
+- 7z archive support when creating a task
+- .vscode/launch.json file for developing with VS code
+
+### Fixed
+- #14: docker-compose down command as written in the readme does not remove volumes
+- #15: all checkboxes in temporary attributes are checked when reopening job after saving the job
+- #18: extend CONTRIBUTING.md
+- #19: using the same attribute for label twice -> stuck
+
+### Changed
+- More strict verification for labels with attributes
+
+## [0.1.1] - 2018-07-6
+### Added
+- Links on a screenshot, documentation, screencasts into README.md
+- CONTRIBUTORS.md
+
+### Fixed
+- GitHub documentation
+
+## 0.1.0 - 2018-06-29
+### Added
+- Initial version
+
+## Template
+```
+## [Unreleased]
+### Added
+-
+
+### Changed
+-
+
+### Deprecated
+-
+
+### Removed
+-
+
+### Fixed
+-
+
+### Security
+-
+```