Version   Changes
--------  --------------------------------------------------------------------
0.13.0    Incompatible changes!
          Fns Unit::symbol and Unit::name now return String (instead of &str).
          Fns Unit::iter and Quantity::iter_units now iterate over Unit (in-
          stead of &Unit).

0.12.0    Added 'serde' support (thx to Roms1383).

0.11.2    Added CI jobs for cargo check, test and clippy (thx to Roms1383).

0.11.1    Added new SI prefixes (thanks to Johann Dirry).

0.11.0    When defining quantity Q = R / S, generate also code for R / Q -> S.

0.10.0    Added crate 'astronomical_quantities'.

0.9.1     Code hygiene based on rustc and clippy lints.
          Added doc comments.

0.9.0     Enhanced formatting of quantity values.

0.8.0     Added trait 'Converter' and generic struct 'ConversionTable' to
          support conversion between quantity values.
          Added pre-defined quantity 'Temperature' (with corresponding
          feature).

0.7.0     Added type Rate, expressing the ratio between two related quantity
          values.

0.6.0     Updated dependency 'fpdec' to version '0.5', thus restricting the
          precision of decimal amounts to 18 fractional digits.
          Moved functions depending on a reference unit from trait 'Unit' to
          the new trait 'LinearScaledUnit'.
          Moved impls of Add, Sub and Mul from trait 'Quantity' to trait
          'HasRefUnit'.

0.5.0     Added pre-defined quantities (with corresponding features):
          - Area
          - Volume
          - Speed
          - Acceleration
          - Force
          - Energy
          - Power
          - Frequency
          - Datathroughput

0.4.2     Changed order of generated code in macro 'quantity' (fixes broken
          doc).

0.4.0     Added fn Unit::from_symbol and fn Unit::from_scale.
          Added fn Quantity::unit_from_symbol and
          fn Quantity::unit_from_scale.
          Removed struct Qty<U> and its generic impls of some std traits.
          Removed type Unitless by implementing trait Quantity directly for
          AmountT.
          Added trait HasRefUnit.
          Enhanced attribute macro 'quantity' to derive a quantity as product
          or quotient of quantities.

0.3.0     Proc-macro 'quantity' – attribute 'unit':
           * Allow int literal as 'scale' param.
           * Added optional 'doc' param.
          Added modules with predefined quantities Mass, Length, Duration and
          DataVolume.

0.2.1     Fixed missing doc attributes in code generated by proc-macro
          'quantity'.
          Fixed cfg attributes to use fpdec.

0.2.0     Replaced macro 'define-qty' by proc_macro_attribute 'quantity'.
          Added impls of traits 'PartialEq', 'Eq' and 'PartialOrd'.
          Added mod prelude.
          Renamed NON_UNIT to ONE.
          Added fn Unit::iter and fn Quantity::iter_units.
          Enhanced documentation.

0.1.0     First public version.