[RFC][PATCH 12/22] JavaHL Ra API Implementation

[[[
    JavaHL: Factor out common java string map processing into StringsTable
class from svn_string_t specific processing in the RevpropTable class

    [ in subversion/bindings/javahl/native ]

    * StringsTable.cpp, StringsTable.h, RevpropTable.cpp, RevpropTable.h
      (m_revprops): Move m_revprops to base class and rename to more
appropriate m_strings
      (RevpropTable): Move constructor logic to base class StringsTable
      (~RevpropTable): Move local reference release from destructor to the
end of the new common constructor as by the end of the constructor all data
has been copied and a reference to java object is no longer required

    * StringsTable.cpp, StringsTable.h
      (hash): New function to create (char *) to (char *) hash from java
Map<String, String> to be used for creating of lock tocken table for
svn_ra_open4 call

    * RevpropTable.cpp, RevpropTable.h
      (hash): Use the new base member variable m_strings instead of
m_revprops
]]]