Fix decoding of single-bit fields.

This fixes, for instance, land-sea masks grib2 files. Thanks goes to
Richard Peter.

http://www.unidata.ucar.edu/support/help/MailArchives/decoders/msg00929.html
Rename enum -> en.

This silences some Java warnings.
Fix up some build issues.
Comment out calls to System.runFinalizersOnExit()

This is deprecated since JDK 1.2 and are only used in profiling.
Commenting out silences some Java warnings.
Add README.md.
Ignore vim and Intellij files.
Fix compile on Java 8.

The original code was causing javac to throw an AssertionError. Working
around the labelled break (by using a flag) seems to fix this fine.
Trying to minimize differences against the original code.