ICMPv6:  Some initial bugfix from first tests of the ICMPv6 auto-configuration logic.  so far so good but a lot more testing is needed

Also remove spaces before and after paretheses to conform to coding standard.

Networking:  Add support for sending ICMPv6 Router Solicitation and receiving Router advertisement.  This is a part of the ICMPv6 auto-configuration logic is still still not complete

On my platform I have just 16-bit timer clocked at 32kHz. As result oneshot timer max delay is 2s. The patch adds limit of maximum ticks in sched_timer_start (nuttx/sched/sched/sched_timerexpiration.c). From Macs N.

Networking:  Fixes another CONFIG_NET_NOINTS issues.  When called sem_timedwait() with the network locked, the network stays logcked while we wait which is not what we want (without CONFIG_NET_NOINTS, interrupts are re-enabled while we wait and all is well).

Auto neighbor solicitation is no longer EXPERIMENTAL and is the default for the DK-TM4C129X/ipv6 configuration

ICMPv6: Adds basic logic to support verification that we have the IPv6 address in the Neighbor Table.  This feature is important because otherwise the first packet sent to a remote peer will fail (it will be replaced with a Neighbor Solicitation).

IPv6: More framework for automatic neighbor solicition.  I think this also corrects and error in a broadcast/multicast address chedk

IPv6: Remove an unusd file (kruft from original IPv6 develoment); Add inital hooks to support automatic Neighbor Solitication

Unix domain:  Enable logic to clean up the FIFOs underlying stream sockets with those sockets are disconnected.  Tehre is still no corresponding clean-up logic in place for Unix domain datagram sockets because the life of the FIFO is not as well known in that case