Quick javadoc warning fixes. [0]

This is mostly just to keep my streak alive...but hey--an improvement is
an improvement!

Another perspective:

https://lkml.org/lkml/2004/12/20/255
Quieting javadoc warnings in RangeProcessor. [0]
Add new IdvObjectStore wrapper class. [1730]

This is a first stab at a simple IdvObjectStore wrapper class that
allows McIDAS-V users to safely and easily read/write to main.xml.

I say "safely" because Jython performs implicit type conversions between
Java and Python types when possible. This is typically pretty convenient
when using Jython, but this behavior can easily call the wrong
(overloaded) IdvObjectStore get/put method...meaning that a call like
the following can end up writing a *long value* to the given property:

  idvObjStore.put("dummy.prop.name", Boolean.FALSE)

Note: the class name may not be final, as this is a nice starting point
for writing a "preferences" implementation entirely seperate from the
IDV.

Assorted niceties:
* All of the "get" methods *require* default values.
* Trying to use method names similar to java.util.prefs.Preferences.
* Has putObject/getObject methods that understand generics.
Add Jython Shell truncation convenience functions.

This commit adds “enableTruncation”, “disableTruncation”, and
“truncation” functions to interactive.py. This is mostly a
proof-of-concept for the JythonObjectStore class (which maybe needs a
context manager for Python’s “with-statement”).

The enable/disable functions probably speak for themselves;
“truncation” merely returns the current value of the
PROP_JYTHON_SHELL_TRUNCATE property.

Suggestions for a better name are very welcome!

[1730]