plugins xep-0060, xep-0277: code simplification/cleaning/fix: - plugin xep-0060: moved rsm data to a more general metadata dict, which will contain all data relative to the node/items set. RSM metadata are prefixed with "rsm_" - plugin xep-0060: minor docstring fixes - plugin xep-0060: removed cache to simplify code base - fixed broken getLastMicroblogs - added _getLastMicroblogs as wrapper to getLastMicroblogs, for bridge - removed lxml dependecy for this plugin, use native twisted instead - several improvments/fixes in item2mbdata