Added Tags, Checkboxes and Radio Buttons components

Merge pull request #127 from adevinta/fix

[Fix] Fixed RadioButton fill color and removed Spark import from prev…

Removed Colors.States.backgroundPressed

Merge pull request #102 from adevinta/feature/colors

[Colors] Removed Colors.States.backgroundPressed

Updated TypographyFontTokenDefault + Added tests

• Removed fontWeight from TypographyFontTokenDefault
• Removed default value if font not found (now does a fatal error like colors)
• Added Tests for Color and Font assets

Finalised Spark Theme

Added SparkColors

Added SparkCore theming capability definition + Spark Demo

Merge pull request #53 from adevinta/feature/border

Update Border

First draft of Spark-iOS configuration and theming capability

Merge pull request #27 from adevinta/theme

Added theme protocols, default structures and spark implementation (Colors, Typography, Border and Layout)