Add a custom collation mechanism

A lot better than that StarDict shitfuckery.

README

@@ -19,7 +19,7 @@ this regard.
 Building and Running
 --------------------
 Build dependencies: CMake, pkg-config, xsltproc, docbook-xsl,
-                    ncursesw, zlib, termo (included),
+                    ncursesw, zlib, ICU, termo (included),
                     glib-2.0, pango, gtk+ (optional, any version)
 
  $ git clone https://github.com/pjanouch/sdtui.git
@@ -45,6 +45,14 @@ argument.  If you want the application to watch the X11 primary selection for
 changes and automatically search for the selected text, use the -w switch.
 This feature requires GTK+.
 
+Extensions
+----------
+As the original StarDict is a bit of a clusterfuck with regard to collation of
+dictionary entries, I had to introduce an additional "collation" field into the
+.ifo file.  When sdtui discovers this field while reading the dictionary, it
+automatically reorders the index according to that locale (e.g. "cs_CZ").
+This operation may take a little while.
+
 Dictionaries
 ------------
 Unfortunately this application only really works with specific dictionaries.