Fixes #3800: Bring new Java bindings to v1.7

---svn-pre-commit-ignore-below---

r29261 [[BR]]
The TargetConditionals.h check is specific to Java -- move it to
ompi_setup_java.m4.

r29262 [[BR]]
Provide Java MPI_Op callbacks via an intercept routine (just like how
we do MPI::Op C++ callbacks).

r29263 [[BR]]
Next generation of MPI Java bindings.

Includes all MPI functions supported by Open MPI, including MPI-3
functions (as of about 2 weeks ago).  Many changes compared to the
prior generation of Java bindings; not much is left from the prior
generation, actually.  The changes include (but are not limited to):

 * Add support for more than just a subset of MPI-1 functions
 * Use typical Java case for symbol names
 * Support Java Direct buffers (giving darn-near "native C"
   performance)
 * Support "type struct" better than the prior generation
 * Make more of an effort for the Java bindings to be a thin layer
   over the back-end C bindings
 * ...and more

A proper README with more information about what is supported, how to
use these bindings, etc. will be committed shortly.

r29269 [[BR]]
New examples for the updated MPI Java bindings

r29270 [[BR]]
Make the Java wrapper compiler behave like the other wrapper compilers
(specifically, with regards to the --showme flag and return code).

r29282 [[BR]]
Add "jdoc" target to make javadocs

r29337 [[BR]]
Add missing include

Refs #3800


r29526 [[BR]]
Cleanup the Java integration - don't install the mpijavac compiler if the user didn't ask for Java bindings