SAMA5:  Hook RTC into build system; Finish RTC alarm logic; Verify correct behavior of the basic RTC functionality

Add instructions to enable RTC in the nsh/ configuration; RTC enabled by default in the demo configuration

Enhanced the FAT32 filesystem code to understand DMA preflight failures, and to use the file sector buffer as a bounce buffer when a user-supplied buffer is not suitable for DMA. From Mike Smith

Enhanced the mmcdd_sdio driver to perform DMA preflight operations and fail DMA read/write requests that fail preflighting. From Mike Smith

net_sendfile:  Let the ACK callback handle the REXMIT flag and don't return until all data has been ACK'd. From Max Holtzberg

Move tcp connection into SYN_RCVD state after aception instead of bypassing and moving directly into ESTABLISHED.  From Max Holtzberg.

SAMA5 LCDC:  Correct how framebuffer memory was being mapped; Remove options to get framebuffer memory in various.  Because of the mapping and aligment requirements, those options really cannot be supported

Changed the meaning of the uip_*input functions. They now return success when a packet is dropped; This is needed for the ENCX24J600 driver that must make a decision to return the packet or not:  It should not retain dropped packets. From Max Holtzberg

Notify the socket layer if a connection is lost before the monitoring callback has been registered.  From Max Holtzberg

SAMA5 LCDC:  Wait when the LCDC is resynchronizing (SIF); Try start-up parameters from Barebox (this still don't work)

SAMA5 LCDC: Move DMA descriptors out of internal SRAM and into SDRAM. I am not completely clear, but it looks like the LCDC cannot support DMA from internal SRAM

Add option to enable Aduino Due specific logic, like pull-up on UART0 RXD.  Suggested by gdi@embedders.org

Make net_close() nonblocking and free unestablished connections if no free connections available.  From Max Holtzberg

Another case where we should use the routing table: There may be multiple routers on the same network.  In that case, we have to search for the routing table for the router that forwards to the destination address.  We do this when we determine the MAC address we want in the ARP logic

netdev_findbyaddr() will not use a routing table if one is available.  It will also make a better decision in the case there there is no routing table but only a single network interface.