Revive config_test.c

Move config-dependent code (recvwithttl) from net.c to mdp_net.c (new)

Move log-implementation-independent code from log.c to log_util.c (new)

Build config_test binary in Makefile
Deprecate RHIZOME_MANIFEST_ID_... in favour of RHIZOME_BUNDLE_ID_...
Consolidate Rhizome string parsing functions

Remove unused rhizome_str[n]_is_...() functions in favour of
str[n]_to_rhizome_..._t() functions

Ensure that all str_to_..._t() functions accept a NULL 'dst' pointer
so they can be used easily to validate strings
Add missing copyright/license comment blocks

Update a few existing copyright notices to reflect recent work
Merge branch 'development' into 'naf4'

Remove two redundant calls to rhizome_retrieve_manifest() in meshms.c,
revealed by an assert() in the stricter manifest parsing code

Fix header files included by socket.h
Merge branch 'naf4' into 'development'

Copyright notices added to most source files and headers

New 'config_test' make target

Add RHIZOME_BUNDLE_ID_xxx, deprecate RHIZOME_MANIFEST_ID_xxx

Consolidate Rhizome string functions