Checkstyle naming conventions were changed to allow most of what's in
wpimath. Naming rules were disabled completely in wpimath since almost
all suppressions are for math notation.
Some valid warnings like throwing NullPointerException or using a for
loop instead of System.arraycopy() were fixed.
Abstract classes marked with PMD.AbstractClassWithoutAbstractMethod were
made concrete because they already had protected constructors.
Fixes#1697.
