Fix Issue #3781 (Case sensitive authz).

* subversion/tests/cmdline/authz_tests.py
  (case_sensitive_authz): Removed XFail decorator.

* subversion/include/svn_config.h
  (svn_config_create) : Documented new parameter.
  (svn_config_read)   : Deprecated.
  (svn_config_read2)  : New function prototype, updated documentation.

* subversion/libsvn_subr/config_impl.h
  (svn_config_t): Added a new boolean called section_names_case_sensitive.

* subversion/libsvn_subr/deprecated.c
  (svn_config_read): New function that calls svn_config_read2
                     with section_names_case_sensitive as FALSE.

* subversion/libsvn_subr/config.c
  (svn_config_create): Added a parameter section_names_case_sensitive
                       which is used to initialize the config.
  (find_option, 
   svn_config_set)   : Added logic to make section names case sensitive.

  (svn_config_read)  : Deprecated.

  (svn_config_read2) : New function that deprecates svn_config_read.
                       Accepts a boolean section_names_case_sensitive,
                       and populates the section names case sensitively 
                       if TRUE.

* subversion/libsvn_repos/authz.c
  (svn_repos_authz_read) : Fixed the caller with 
                           section_names_case_sensitive as TRUE.
* subversion/tests/cmdline/atomic-ra-revprop-change.c
  (construct_config) : Fixed call of svn_config_create.
Patch by: Arwin Arni <arwin{_AT_}collab.net>