Remove obsolete plug-ins

I thought it might be wise to remove obsolete plug-ins from the master
branch; if someone wants to resurrect them, they can always get them
from an earlier commit. I've also updated the documentation to reflect
this.
Silence some warnings about unclosed resources

The warnings were all false-positives.
Remove unused import
Remove unnecessary semicolons
Remove unnecessary casts
Add missing @Override annotations

These were added by Eclipse, so the formatting might not be perfect;
it should be cleaned up at some point separately.
Qualify statics with the class that defines them

Ensure static methods and fields are accessed through the class or
interface where they are declared.
Mark deprecated declarations with @deprecated

Declarations with a `@deprecated` field in their JavaDoc should also
have a `@deprecated` annotation.
Remove unnecessary null check
Remove unnecessary superinterfaces
Fix JavaDoc warnings

This mostly consists of removing non-existent parameters and thrown
exceptions.
Increase compiler compliance to JavaSE 6

Prevent features from Java 6 from being reported as errors.
Fix raw type/unchecked conversion warnings

All false positives. Most of the raw type warnings could only be
eliminated by silencing them with an annotation. A few project settings
had @SupressWarnings annotations disabled, so those settings needed to
be changed.
Merge pull request #192 from ianbollinger/remove-dead-plugins

Remove obsolete plug-ins
Merge pull request #194 from ianbollinger/clean-warnings

Eliminate a number of compiler warnings