Implement ExcludeTags, with tests. Fixes #231
Update changelog

Fixes #231
Different color schemes for dark and light backgrouds

There is only limited amount of colors that are readable on both
DarkBlue (ISE, Console) and White (PowerGUI) backgrounds. To use more
colors these have to be differentiated with Dark and Light color
schemes.
Update version to 3.2.0

Updating the version to check automatic publish to NuGet and choco.