Log Message:
Update to 1.5.6.

Version 1.5.6
(27 Feb 2009, from /branches/1.5.x)
http://svn.collab.net/repos/svn/tags/1.5.6

 User-visible changes:
  * allow colons within mergeinfo path names (r35040)
  * make it impossible to add .svn to wc via 'svn add --parents' (r35143, -5)
  * copy properties of added but uncommitted files (r32448)
  * speedup JavaHL bindings on Windows (r35733)
  * improve performance of log operation on < 1.5 servers (r35566)
  * allow commits over Neon of files >2GB (POSIX only) (r34919, -24)
  * allow serf from behind MS ISA proxy servers (r35981)
  * prevent svnmerge-migrate-history.py from committing bogus mergeinfo (r35516)

 Developer-visible changes:
  * fix error handling in mod_dav_svn (r35250, -86)
  * support --server-minor-version in windows testsuite (r31393)
  * fix depth_tests.py 23 on Windows with a BDB repo (r34875)
  * allow svn_mergeinfo_parse() to tolerate unordered mergeinfo (r35297, -367)
  * allow overlapping rangelists into svn_mergeinfo_parse() (r35466, -712, -713)