Implement svn_ra_get_file_revs in JavaHL.

[in subversion/bindings/javahl/src/org/apache/subversion/javahl]
* ISVNRemote.java (ISVNRemote.FileRevision): New nested class.
  (ISVNRemote.getFileRevisions): New.
* remote/RemoteSession.java (ISVNRemote.getFileRevisions): Declare native.

[in subversion/bindings/javahl/native]

* RemoteSession.h (RemoteSession::getFileRevisions): New prototype.
* RemoteSession.cpp (FileRevisionHandler): New helper class.
  (RemoteSession::getFileRevisions): Implement.
* org_apache_subversion_javahl_remote_RemoteSession.cpp
  (Java_org_apache_subversion_javahl_remote_RemoteSession_getFileRevisions)
   Native wrapper for ISVNRemote.getFileRevisions.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1510494 13f79535-47bb-0310-9956-ffa450edef68