Build script working again.

includeantruntime tells ant whether to use your environment variables
when building your java files. It's pretty important to set to true
in many cases, even though ant tells you to set it to false.
Without it, javac was ignoring JAVA_HOME.
Added information about JAVA_HOME to README.md
Merge https://github.com/processing/processing-web into field-method-disambiguiation
Added a small java file for testing reference builder.

Field/method issue in @see tags can be demonstrated with this.
Changes to @see tag evaluation.

No longer caching fields/methods of class when evaluating see tags.
Viewing output from a full build, I didn't see anywhere that it was
making a useful difference to cache fields/members by name, and it
definitely caused a bug. Leaving code in but commented out in case
we discover some other issue that this causes.

Only gathering misplaced @see tags for methods (not fields). This
prevents fields with the same name as methods from having funny
"See also:" references to themselves.

Fixes github issue 137.