Add scalastyle config.
Disabled the newling-at-EOF check, as it appears to serve no useful
purpose.
Fixed a number of Scalastyle warnings, mostly public methods with no
type.
Disabled Scalastyle's rule against using nulls. It's generally a good
idea, but this project does a lot of java interop, so nulls are often
required.
Cleaned up most of the wildcard imports.
Fixed more Scalastyle warnings.
Fixed violations of some scalastyle rules where it makes sense to do so,
then disabled them.

Disabled the scalastyle rule about using returns, because early returns
are useful. Allow if expressions to have no braces even if the if/else
pair is split up over two lines. Disabled the rule about repeated string
literals, as this will be used often for the @Optional annotations.
Added a better logging system and replaced printlns.
Disabled the magic number warning and fixed the rest of the scalastyle
warnings.
Disabled the return and null rules the right way.
Finish refactoring-scalastyle. fixes #18