v3.5.0

• Adds a new optimisation path which can minimise keyword values for
  background-position and the background shorthand.
• Tweaks to performance in the core module, now performs less AST passes.
• Now compiled with Babel 6.

v3.4.0

• Adds a new optimisation path which can minimise gradient parameters
  automatically.

v3.3.2

• Fixes an issue where using options.safe threw an error when cssnano was
  not used as part of a PostCSS instance, but standalone (such as in modules
  like gulp-cssnano). cssnano now renames safe internally to isSafe.

v3.3.1

• Unpins postcss-colormin from 2.1.2, as the 2.1.3 & 2.1.4 patches had
  optimization regressions that are now resolved in 2.1.5.

v3.3.0

• Updated modules to use postcss-value-parser version 3 (thanks to @TrySound).
• Now converts between transform functions with postcss-reduce-transforms.
  e.g. translate3d(0, 0, 0) becomes translateZ(0).

v3.2.0

• cssnano no longer converts outline: none to outline: 0, as there are
  some cases where the values are not equivalent (thanks to @TrySound).
• cssnano no longer converts for example 16px to 1pc by default. Length
  optimisations can be turned on via {convertValues: {length: true}}.
• Improved minimization of css functions (thanks to @TrySound).

v3.1.0

• This release swaps postcss-single-charset for postcss-normalize-charset,
  which can detect encoding to determine whether a charset is necessary.
  Optionally, you can set the add option to true to prepend a UTF-8
  charset to the output automatically (thanks to @TrySound).
• A safe option was added, which disables more aggressive optimisations, as
  a convenient preset configuration (thanks to @TrySound).
• Added an option to convert from deg to turn & vice versa, & improved
  minification performance in functions (thanks to @TrySound).

v3.0.3

• Fixes an issue where cssnano was removing spaces around forward slashes in
  string literals (thanks to @TrySound).

v3.0.2

• Fixes an issue where cssnano was removing spaces around forward slashes in
  calc functions.

v3.0.1

• Replaced css-list & balanced-match with postcss-value-parser, reducing the
  module's overall size (thanks to @TrySound).