Prepare v6.0.0 release (1st PS 0.15.0-compatible release) (#164)

* Update the bower dependencies

* Uncomment spago tests

* Update the changelog

Prepare v5.0.0 release (#130)

Co-authored-by: Thomas Honeyman <admin@thomashoneyman.com>

Merge pull request #77 from justinwoo/compiler/0.12

changes for 0.12

Merge pull request #72 from safareli/colors

update ps-colors version range

Merge pull request #71 from garyb/re-exports

Update re-exports to include missing values and types

Merge pull request #70 from garyb/font-style

Add font-style values

Merge pull request #67 from garyb/update-build

Update build

Merge pull request #60 from justinwoo/0.11

update for 0.11

Merge pull request #49 from alexmingoia/topic/list-style-rule

Add list-style rule