Extend JavaHL's diff to accept options controlling the output format.

[in subversion/bindings/javahl/src/org/apache/subversion/javahl]
* types/DiffOptions.java (DiffOptions): New class, encapsulating a number
   of options that control the format of the diff output.
* ISVNClient.java, SVNClient.java (ISVNClient.diff): Added four more
   overloads (two of which are implemented as native methods)
   that accept an additional DiffOptions parameter.

[in subversion/bindings/javahl/native]
* DiffOptions.h, DiffOptions.cpp (DiffOptions):
   New class, C++ mirror of the Java class DiffOptions.
* SVNClient.h, SVNClient.cpp (SVNClient::diff): Update native implementation
   to accept an aditional DiffOptions reference parameter.
* org_apache_subversion_javahl_SVNClient.cpp
  (Java_org_apache_subversion_javahl_SVNClient_diff): Update native wrapper.

* subversion/bindings/javahl/tests/org/apache/subversion/javahl/BasicTests.java
  (BasicTests.testDiffOptions): New test case for diff with options.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1456321 13f79535-47bb-0310-9956-ffa450edef68