Make .o files in separate subdirectories for servald and library
Factor struct __sourceloc and __WHENCE__ from "log.h" into "whence.h"
Factor sid_t etc from "serval.h" into "serval_types.h"
Factor rhizome_bid_t etc from "rhizome.h" into "rhizome_types.h"
Do not include "serval.h" in library sources
Add log_stderr.c and logMessage.c for stand-alone executables
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
Remove stowSid() at last
Change API of tohex() and strbuf_tohex(), to pass string length instead of
binary byte count. This allows odd numbers of hex digits to be produced.
Remove alloca_tohex_sid(); replace with alloca_tohex_sid_t()
New alloca_tohex_sid_t_trunc() macro
Move lots of non-Serval-specific string functions from "serval.h"/dataformats.c
to "str.h"/str.c.
Add str_fromprint() function that reverses the effect of toprint(): interprets
escape sequences in the source string "\n\t\r\0\xHH\\" and replaces them with a
single char in the destination string.
