Fix ws_transaction_command_list
Merge pull request #234 from neithernut/add-deserializer-prequisites

Fix ws_transaction_command_list
Add common header for yajl backend
Add common.c for yajl JSON backend including stubs
Add allocation function callbacks including stubs
Add allocation func table
Add implementation for serializer_yajl_state_new()
Add implementation of serializer_yajl_state_free()
Add JSON deserializer backend interface definition
Add deserializer file with stubs
Add yajl callbacks definitions and stubs
Add YAJL callback table
Add implementation for ws_serializer_json_deserializer_new()
Add deserialize callback with stub
Pass deserializer as context around
Pass size to yajl state object allocation

This way, the yajl state object becomes an abstract one
Add deserializer state type including allocator helper
Add start_map callback implementation
Add file for magic constants
Add (partial) implementation of string callback