* wip
* fix build failure and test failures for FreeRTOS IP unit tests
* new ip diffconfig 1 included in build
* updating prvProcessUDPPacket() as per PR #689 and fixing tests
* wip ip diffconfig
* added diffconfig2 for ip unit tests wrt to diffconfig with ipconfigCOMPATIBLE_WITH_SINGLE set as zero to enable FreeRTOS_IP_init tests and fixed freertos ip diffconfig unit tests
* minor fix on an ARP unit test
* minor fix with ip utils diffconfig unit tests build
* Fixed build failure with ip diffconfig 1 and 2. Pulled latest changes from dev/v6 branch.
* Removed unused code.
