query_classifier.h: added QUERY_TYPE_CREATE_TMP_TABLE and QUERY_TYPE_READ_TMP_TABLE for use of temporary table support.
hashtable.c:Added variant of hashtable which is 'flat', that is, stored to existing memory instead of allocating memory as a part of the call. Existing function declarations don't change but added hashtable_alloc_flat for the purpose. Both hashtable_alloc and hashtable_alloc_flat now call the real allocation function, hashtable_alloc_real. hashtable_free only frees memory which is allocated in hashtable_alloc_real.
hashtable.h: added a flag to HASHTABLE struct to indicate whether hashtable owns its memory or not.
readwritesplit.h: Added RSES_PROP_TYPE_TMPTABLES property type to be used for keeping the hashtable for tablenames.
readwritesplit.c: Added comments about temporary table support implementation.
query_classifier.h: added parsing information structure to query classifier away from buffer.h.
buffer.c:introduced a buffer object which includes object pointer and a clean-up call-back function. Buffer objects form a list which is cleaned up by the last referrer of the buffer, as a part of gwbuf_free. Buffer object list is protected by a spinlock gwbuf_lock.
Also added identifier type, bufobj_id_t which is enumerated type and currently includes one value only, GWBUF_PARSING_INFO. Added also a bitfield for information about the buffer. It currently has one type only, GWBUF_INFO_PARSED indicating that buffer content is parsed and there is buffer object of type GWBUF_PARSING_INFO.
skygw_utils.cc:replace_literal:changed regexec matching to case insensitive because user-defined literals are sometimes converted to upper-case ones.
skygw_utils.cc: removed replace_str and implemented replace_literal which replaces user-provided literals in query with predefined string "?". Replacing is done one by one, so it is suboptimal ipmlementation since all literals could be passed to replacement function in one call and processed all before returning.
query_classifier.cc: Now query can be parsed outside query_classifier_get_type by calling function parse_query. It creates parsing_info_t struct which is then added to the GWBUF which also includes the query. Parsing information follows the buffered query and it is freed at the same time with query buffer, in gwbuf_free.
buffer.c: additions of parsing information to gwbuf struct.
modutil.c: added function which returns query from GWBUF in plain text string.
readwritesplit.c:routeQuery now only calls query_classifier_get_type to get the query type instead of extracting plain text query from the GWBUF buffer.
mysql_common.c:gw_MySQL_get_next_packet didn't handle case where an insert command followed by alter table in the same read buffer. It shouldn't been possible without multi-statement being set.
