v0.0.9

Bug fixes:

• @for/@while inside @content block (@sergeylukin)
• functions in mixin_content (@timonbaetz)
• infinite loop when target extends itself (@oscherler)
• function arguments are lost inside of @content block

Enhancements:

• allow setting number precision (@kasperisager)
• public function helpers (toBool, get, findImport, assertList, assertColor, assertNumber, throwError) (@Burgov, @atdt)
• add optional cache buster prefix to serve() method (@iMoses)