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.
log_manager.cc: fixed block buffer overflow. Queries are logged to trace log and long queries exceed the bufsize in length. Those were written beyond allocated memory areas.
mysql_client_server_protocol.h: added mysql_protocol_state_t to indicate whether MySQL protocol object is allocated, usable or freed. Freed means that memory allocations made by the protocol are freed. That is, command history etc.
mysql_backend.c: gw_backend_hangup and gw_error_backend_event used to call error handling function although session was already closing. Added check for session state.
mysql_client.c: route_by_statement lost some packets in case where query was sent in multiple packets.
mysql_common.c: gw_MySQL_get_next_packet failed in packet handling with route_by_statement. When multi-packet query was merged into one, packet type wasn't copied.
protocol_archive_srv_command and mysql_protocol_done didn't have proper locking in place which lead to occasional crashes.
