SAMA5D4:  More progress on XDMAC driver (still no complete); Also fixes some critical errors in the SAMA5D3 DMA definitions

Move include/nuttx/net/uip/uip-arch.h to include/nuttx/net/arp.h; rename all uip_arp_ functions to arp_

Move include/nuttx/net/uip/uip-arch.h to include/nuttx/net/arp.h; rename all uip_arp_ functions to arp_

snprintf():  If size is zero, then snprintf() should return the size of the required buffer without writing anyting.  From Sami Pelkonen

Move prun from interpreters/ to system/;  And an NSH built-in appliation that can be used to execute P-Code files from the NSH command line

Create P-Code execution helper in apps/interpreters/prun; The P-Code binary format is functional except that there are still some modularity and kernel build issues that need to be addressed.

P-code BINFMT:  Add logic to pass information from the binfmt logic to the P-code interpreter.  This includes some extension to the binfmt interfaces.

Update the displayed I2C on each get iteraction (not the same starting address).  From Ryan VanSickle

The alternate console device CONFIG_NSH_CONDEV must not be defined unconditionally.  This causes errors when using Telnet sessions.  This was solved by adding CONFIG_NSH_ALTCONDEV: CONFIG_NSH_ALTCONDEV enables or disables the feature then, if enabled, CONFIG_NSH_CONDEV provides the alternative console device name

Update configuration an make logic in order to select that the serial blaster task priority and stack size. From Bob Doiron

Updated changelogs and release notes in preparation for the 7.2 release.  Still need to do a little more before the release