changelog
    
    
    - Mon, 20 Dec 2021 12:10:48 +0100
 
    - by Mike Becker <universe@uap-core.de> [Mon, 20 Dec 2021 12:10:48 +0100] rev 479
 
    - add linked list tests for cxListAt()
 
    - Mon, 20 Dec 2021 11:58:36 +0100
 
    - by Mike Becker <universe@uap-core.de> [Mon, 20 Dec 2021 11:58:36 +0100] rev 478
 
    - add more nonnull attributes
This also changes the contract for last/first in the sense that these
functions now also require a valid pointer. 
    - Mon, 20 Dec 2021 11:26:39 +0100
 
    - by Mike Becker <universe@uap-core.de> [Mon, 20 Dec 2021 11:26:39 +0100] rev 477
 
    - add more explicit documentation to cx_linked_list_remove()
also require nonnull node argument 
    - Mon, 20 Dec 2021 11:17:06 +0100
 
    - by Mike Becker <universe@uap-core.de> [Mon, 20 Dec 2021 11:17:06 +0100] rev 476
 
    - change contract of cx_linked_list_remove()
also use cx_linked_list_remove() in high level API 
    - Sat, 04 Dec 2021 17:38:23 +0100
 
    - by Mike Becker <universe@uap-core.de> [Sat, 04 Dec 2021 17:38:23 +0100] rev 475
 
    - add cx_linked_list_first() + cx_linked_list_prepend()
removes concatenating behavior of cx_linked_list_add() 
    - Sat, 09 Oct 2021 11:12:48 +0200
 
    - by Mike Becker <universe@uap-core.de> [Sat, 09 Oct 2021 11:12:48 +0200] rev 474
 
    - remove cxListLast (can be realized via cxListAt and index=size-1)
 
    - Fri, 08 Oct 2021 19:47:31 +0200
 
    - by Mike Becker <universe@uap-core.de> [Fri, 08 Oct 2021 19:47:31 +0200] rev 473
 
    - add cx_linked_list_{prev, remove, reverse}
changes assertions for some low level methods (loc_next is now always mandatory) 
    - Fri, 08 Oct 2021 18:58:49 +0200
 
    - by Mike Becker <universe@uap-core.de> [Fri, 08 Oct 2021 18:58:49 +0200] rev 472
 
    - move dereference operation into macro
 
    - Tue, 05 Oct 2021 16:22:48 +0200
 
    - by Mike Becker <universe@uap-core.de> [Tue, 05 Oct 2021 16:22:48 +0200] rev 471
 
    - add new ucx_list_sort test
 
    - Wed, 06 Oct 2021 14:24:52 +0200
 
    - by Mike Becker <universe@uap-core.de> [Wed, 06 Oct 2021 14:24:52 +0200] rev 470
 
    - add tree.h to list of headers