Release v2.4.0

- Fix diffusion velocity formula. It eliminates outlying vortices and
  spikes (noise) in resulting forces.

- Significantly refactor command-line UX and update README.

- Merge `vvcompose` functionality with `vvflow`. The symlink is
  preserved for the compatibility.

- Remove obsolete `vvgen` script. Its functions are performed by `vvflow`.

- Add `gpquick --size` option for adjusting image size.

- Write `gpquick` resulting image to the `--output` file instead of stdout.

- Add `gpquick --dump-script` option which prints the gnuplot sctipt to stdout.

- Revise manpages `man vvflow`, `man vvxtract`, `man vvplot`.

- Provide `--help` option for all commands in addition to manpages.

Release v2.3.0

Added

- `vvplot --eps` option for fine-tuning streamlines, vorticity and
  pressure fields smoothing factor.

Fixed

- Building instructions.
- Compilation errors with GCC 13.

Release v2.2.2

Added

- Savonius shape generation for `vvcompose`.
- Binary packages for ubuntu jammy (22.04).

Release v2.2.1

Fixed

- Upload packages for ubuntu focal and groovy.
- Revise the readme.

Release v2.2.0

Added

- New vvplot option `-U` for plotting a velocity field.
- New vvplot option `--load-field` for plotting side-prcessed fields.

Changed

- Replace `libmatheval` processor with Lua.
- Build (almost) all third-party libraries statically.
- Move CI from Bitbucket to the GitHub.
- Replace `googletest` testing framework with `cppunit`.

Fixed

- Segmentation fault in vvplot due to stack-use-after-scope bug.

vvflow v2.1.3

Fixed:

* Condition for using inverse matrix
* Signs in Newton equation
* Accounting friction forces

vvflow v2.1.2

Added:

* Support for negative spring damping coefficient
* New vvplot --ref-xy option values: "bx", "by"

Fixed:

* vvencode video quality

vvflow v2.1.1

Fixed:

* External torque formula

vvflow v2.1.0

Fixed:
* Zero area formulae

Added:
* Setting external torque in holder

vvflow v2.0.0

Changed:
* cmake-based build
* bitbucket-ci integration
  - gtest unit testing
  - pytest integration tests
  - deb packages published
* man pages included
* vvcompose rewritten in C++
  - built-in lua interpreter
  - built-in bodies generation
* vvxtract rewritten in C++
  - handles both results and stepdata
* vvplot rewritten in C++
  - able to save intermediate tar archives