CSS Parser Code

unknown rule values are printed as ems instead of em

update dependencies and enforce maven/java version

tag version 0.9.29

improved deploy process

small javadoc fixes

prepare 0.9.29 release

new CSSFormat setting useSingleQuotes to force the usage of single quotes instead of double quotes

support for the dimensions 'ch', 'vw', 'vh', 'vmin' and 'vmax' added (CSS3)

Minus sign no longer supported inside unknown dimensions (CSS3).
This fixes a problem when parsing calc terms without whitespace around the minus like in calc(42vh-16.4em).

missing override annotations added

tag

prepare 0.9.28 release

jdk 1.8