api: add_stat functions are now generated using define
core: function to get all tree nodes with specified action_code added
aggregators: actions_set is now passed to aggregator in constructor
aggregators: histogram aggregator added
tests: histogram tests added. fix in aggregators constructors
examples: stats example fixed
examples: histogram aggregator example added
aggregators: parent_call_tree aggregator added
core: function to get call_tree's map<action_code, nodes> added
aggregators: complex_aggregator added
aggregators: category_filter_aggregator added
examples: category_filter_aggregator example added
aggregators: filter aggregator removed
api: actions_set is now static singleton
examples: duplicate define_new_action removed
aggregators: memory leak with strings pushed into rapidjson fixed