Further elaborated license statements in README

Author: Felix Exner

README.md

@@ -96,6 +96,20 @@ add_executable(db_client main.cpp)
 target_link_libraries(db_client ur_client_library::urcl)
 ```
 
+## License
+The majority of this library is licensed under the Apache-2.0 licensed. However, certain parts are
+licensed under different licenses:
+ - The queue used inside the communication structures is originally written by Cameron Desrochers
+   and is released under the BSD-2-Clause license.
+ - The semaphore implementation used inside the queue implementation is written by Jeff Preshing and
+   licensed under the zlib license
+ - The Dockerfile used for the integration tests of this repository is originally written by Arran
+   Hobson Sayers and released under the MIT license
+
+While the main `LICENSE` file in this repository contains the Apache-2.0 license used for the
+majority of the work, the respective libraries of third-party components reside together with the
+code imported from those third parties.
+
 ## Library contents
 Currently, this library contains the following components:
  * **Basic primary interface:** The primary interface isn't fully implemented at the current state

include/ur_client_library/queue/LICENSE.md

@@ -1,7 +1,6 @@
-This license applies to all the code in this repository except that written by third
-parties, namely the files in benchmarks/ext, which have their own licenses, and Jeff
-Preshing's semaphore implementation (used in the blocking queue) which has a zlib
-license (embedded in atomicops.h).
+This license applies to all the code in this folder except that written by third parties, namely
+Jeff Preshing's semaphore implementation (used in the blocking queue) which has a zlib license
+(embedded in atomicops.h).
 
 Simplified BSD License:
 

package.xml

@@ -13,6 +13,7 @@
   <license>Apache-2.0</license>
   <license>BSD-2-Clause</license>
   <license>Zlib</license>
+  <license>MIT</license>
 
   <url type="website">http://wiki.ros.org/ur_client_library</url>
   <url type="bugtracker">https://github.com/UniversalRobots/Universal_Robots_Client_Library/issues</url>