builds of add-ons projects: one pair of LICENSE & NOTICE

[Marshall Schor <ms...@schor.com>]

The individual add-on projects (for instance, the WhitespaceTokenizer), are
designed to be consumed individually, as well as possibly being packaged
together in a binary "addons" distribution.  The main built artifact, a JAR
file, typically, only has the compiled source classes.  The binary distributions
typically contain, in addition, dependencies needed by the project (other JARs,
etc.).

For some of our other projects (e.g., the UIMA SDK), we keep a top-level
LICENSE/NOTICE file pair that is for the "source" (only) distribution, plus a
LICENSE/NOTICE pair (inside a src/main/readme/ directory, usually) which is for
the "binary" distribution.

The binary distribution version of the LICENSE/NOTICE files incorporates LICENSE
and NOTICE requirements of the "other" things (such as required dependencies)
being distributed with the binary distribution.

Having both versions I think enhances the consumability of our work, as it
allows down-stream users who will be distributing sources or Jars based on the
sources (without dependencies) to have shorter, less-complex LICENSEs/NOTICEs;
often these are just the standard Apache versions.

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Our addons projects are not (currently) following these conventions, but rather
have just LICENSE/NOTICE files at the top level that are for the
distribution-with-dependencies.  I'm thinking of changing this to the 2-version
style; what do others think? 

-Marshall