Recursive mutex can be locked multiple times by a single thread they
are initialitzed by lumiera_recmutex_init() and used by LUMIERA_RECMUTEX_*
macros.
Chained mutex use the mutexacquirer from the outer scope now. Maybe its
later needed to pass acquirers explicit, we will see.
Acquiring mutexes is now wraped in a easy to use MUTEX_SECTION macro.
This scheme will be extended for chained lock propagation soon.
Notes:
* NoBug resourcemanagement is now part of the lower layer,
RESOURCE_ENTER/RESOUCE_LEAVE are maintained automatically
* one must still call RESOURCE_ANNOUNCE/RESOURCE_FORGET, because we want
to maintain high level information about resources.
* MUTEX_SECTIONS must not be left with any kind of jump
