Test linked Matroska files (manually)

Editing linked Matroska files works. The linked
files are treated as individual files. When saving
segment linking is retained and the files aren't
otherwise broken.

Author: Martchus

README.md

@@ -43,9 +43,8 @@ For examples check out the command line interface of [Tag Editor](https://github
 API documentation can be generated using Doxygen with `make tagparser_apidoc`.
 
 ## Bugs, stability
-- Matroska files composed of more than one segment aren't tested yet and might not work
-- It is recommend to create backups before editing because I can not test whether the library
-  works with all kinds of files (when forcing rewrite a backup is always created)
+It is recommend to create backups before editing because I can not test whether the library
+works with all kinds of files (when forcing rewrite a backup is always created).
 
 ## Build instructions
 The tagparser library depends on [c++utilities](https://github.com/Martchus/cpp-utilities) and is built
@@ -55,5 +54,4 @@ library is required.
 
 ## TODO
 - Support more formats (EXIF, PDF metadata, Theora, ...)
-- Do tests with Matroska files which have multiple segments
 - Support adding cue-sheet to FLAC files