Rename last pico_free to PICO_FREE

remove unused parameter warnings from compilation

Merge branch 'dev' - Release 1.6.0

TCP: socket garbage collector timeout set to 3 seconds

Remove old check from fragments module

Aesthetic fixes. Code formatting.

Moved websockets to picotcp-modules

pico_rand_feed made weak for external pools feeding.

Added link status call to the device driver interface

make sntp client compatible with IAR