Complete reworked and beautified the Broadcast Manager (bcm)

Complete reworked and beautified the Broadcast Manager (bcm)
The BCM now supports the binding to ifindex 0 like the raw socket does.
The first implementation of the BCM was from September 2003 and therefore
many historic stuff (e.g. unusual error reporting) was removed.
The support of ifindex 0 leads to the possibility to read from several
interfaces via one BCM-socket using sendto() / recvfrom().
See new test-apps tst-bcm-?x-sendto.c
The update of RX/TX_SETUPs 'on the run' are only possible with a smaller or
eval size of parameters now, as it is very complex in locking to provide the
other case and there was really now use-case for it ...

git-svn-id: svn://svn.berlios.de//socketcan/trunk@138 030b6a49-0b11-0410-94ab-b0dab22257f2