Networking: setsockopt() fails when setting timeouts to values less that an 100 msec.  That is because the timeout is limited to stops of 1 decisecond and because the conversion of structure timeval was truncating the microsecond remainder.  The utility net_timeval2dsec now accespts and option to determin how it handles the remainder:  truncate, discarding the remainder, use the remainder to round to the closed decisecond value, or use any non-zero remainder to the next larger whole decisecond value.

For the setsockopt() case, it will always use the final option.  This means that a time of zero (i.e., not timeout) can only occur if the value zero was explicated provided to setsockopt().

net_startmonitor.c always returned zero.  In the case where a socket has already been closed, it correctly handled the disconnetion event but still returned OK.  Returning OK causes the callers of net_startmonitor to assume that the connection was okay, undoing the good things that net_startmonitor did and causing the socket to be marked as connected.  This behavior was noted by Pelle Windestam.

Networking:  Fixes an important TCP bug: 16-bit flags was being converted to 8-bits in a few locations, causing loss of status indications

Networking:  No that ARP, ICMP, and ICMPv6 reside in the same list we need to make the definitions of ARP_POLL, ICMP_POLL, and ICMPv6_POLL different because there are small differences in the context for each.

Extend device specific callbacks to ICMPv6 and ARP.  Fix some IPv6 compilation errors that have crept in

Basic support for the Kinetis K20 architecture.  Taken from PX4.  This is the work of Jakob Odersky.

SAML21-Xlplained: Add options to enable XOSC32K and to use it as the DFLL source; NSH configure now uses DFLL with OSC16M source

Logic that samples the free running counter reads the pending interrupt status regsiter and can cause interrupts to be lost.  So, if when the status regsiter is read, the logic must also handle the timer overflow event.  Found and fixed by Max Neklyudov