* remove some include cruft
* remove some include cruft

* (SVN_RA_ABI_VERSION): new define and doc on what it means

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion