Revert removal of support for <user pref. dir>/data/units

RELEASE_NOTES

@@ -19,10 +19,6 @@ to test this feature and report bugs when found.
 Users of Wesnoth 1.5.0 are encouraged to upgrade since Wesnoth 1.5.0 won't be
 compatible with recent changes to the addon server.
 
-Support for keeping unit WML in <user preferences dir>/data/units for testing
-has been removed. Content authors are encouraged to use the UMC directory
-for such purpose.
-
 Now content authors can specify the type of their addons. See the documentation
 updates at http://www.wesnoth.org/wiki/PblWML for details.
 

changelog

@@ -112,7 +112,8 @@ Version 1.5.0+svn:
      (patch #1066)
    * Fixed unstoned units not having their attacks at their first turn
    * Prevent steadfast ability from lowering resistance if already over 50%
-   * <user data dir>/data/campaigns directory is created on first run
+   * <user data dir>/data/campaigns and <user data dir>/data/units
+     directories are npw created on first run
    * added command line parameter --config-path, which prints the path to the
      config directory and exits
    * fix a bug with variable substitution time of [event]-within-[event]

data/core/units.cfg

@@ -9,6 +9,7 @@
 
 [+units]
     {core/units}
+    {~units}
     # subfolders for units
     {core/units/bats/}
     {core/units/boats/}

src/filesystem.cpp

@@ -420,6 +420,7 @@ std::string get_user_data_dir()
 		_mkdir("userdata/data/multiplayer");
 		_mkdir("userdata/data/maps");
 		_mkdir("userdata/data/maps/multiplayer");
+		_mkdir("userdata/data/units");
 		_mkdir("userdata/saves");
 		inited_dirs = true;
 	}