* parse all OIDs earlier, detect all wrong OIDs before any query
is made (GET-operations)
* introduce ERRNO_MULTIPLE_SET_QUERIES:
warn if request contains more OIDs than max_oids and SET operation
(and type&value checks) will be done in chunks.
fix set method when request contains more OIDs than max_oids (2nd and
subsequent chunk were ignored)
of last SNMP-related error
* formatting markup
* some fixes in max_oids logic: NULL will set it to default value,
do not allow non-positive user-supplied values
* unit tests for changes