Added all colours from FlatUIColors.com

Added
 
TURQUOISE (aliased as "turquoiseflatui" as turquoise already exists)
EMERALD
PETER RIVER
AMETHYST
WET ASPHALT
GREEN SEA
NEPHRITIS
BELIZE HOLE
WISTERIA
MIDNIGHT BLUE
SUN FLOWER
CARROT
ALIZARIN
CLOUDS
CONCRETE
ORANGE (aliased as "orangeflatui" as orange already exists)
PUMPKIN
POMEGRANATE
SILVER (aliased as "silverflatui" as silver already exists)
ASBESTOS

TODO:
Bring in more flatUI colours and implement a palette load where .json palettes can be passed to override the in-built palette