This reverts commit ed491742a1, reversing
changes made to 12f316f8c8.
Before this goes in, we should first auto detect bright vs dark terminal
background and default to different themes in those two cases: #67
Before this change, if you had a hyperlink followed by unstyled text,
moar wouldn't reset the hyperlink property, messing up everything after
it.
With this change in place, that now works as one would expect.
Fixes#169.
StyleDefault is all zero values, so we can simplify the definition. If that
changes in the future (not likely) we can go back to the old definition method.
Fixes#57
