xmlrpc: added guardian define for http.h and fixed usability by defaulting to system malloc

- with pkg the module is barely usable due to large overhead of xml tags
xmlrpc: keep pkg for sip message related ops
mtree: rpc mtree.summary returns an array to comply with xmlrpc format
mtree: rpc mtree.summary can take as parameter the name of the tree
mtree: docs updated for mtree.summary
xmlrpc: fixed optional parameter read handling
xmlrpc: don't generate internal xmlrpc reply for optional parameter read
mtree: return 404 if mtree is not found for rpc mtree.summary
mtree: store reload count and timestamp for trees

- print these details via mi/rpc summary command
- count is not stored when reload many tables from one table (cannot
  easily get reference to the previous loaded tree structure)
mtree: shift values for reload count and time from temporary structure
sercmd: refactored reading the rest from socket on reply too long

- patch by by Savolainen Dmitri, FS#422
htable: set RET_ARRAY flag for rpc commands returning more than one value

- fix failure in xmlrpc parsing
rtpengine: support ICE=force_relay flag

author: Juha Heinanen <jh@tutpro.com>
modules/rtpengine: documented 'force_relay' ICE flag value
tm: reset local lock reply status after functions that do unlock
core: new rpc api to add values in an array

- memeber named array_add
ctl: fifo server implementation was lacking adding struct values

- specifier '{' was not handled for adding values
- implemented adding array with '[' specifier
- array_add aliased to rpc_struct_add for the moment
ctl: init binrpc callbacks in mod init and implement '[' specifier

- '[' allows adding an array
- implemented rpc api member array_add
xmlrpc: implemented specifier '[' for array

- it is only for add operations (no scan)
- implemented new rpc member array_add
xhttp_rpc: added handling for specifier '['

- add array into rpc result
- new rpc api member aliased to rpc_struct_add (needs update for proper
  array value insertion)