Merge pull request #62 from chipdude/chip/x_backoff

use std::ref() in backoff.  also add feature(?) of variable growth scale
don't use std::bind in backoff
add checks in ewma test
return exit status from task::main. use wait_for_tasks in spawn_thread.
change to fix bug in g++-4.7 parsing
make entry public for integration with other frameworks
introduce method name matching into HTTP server routing
add hs::app_json hs::app_json_utf8
uri: use std::forward where appropriate
introduce sliding time aggregate statistics
use nostacksize_t to evolve deprecated APIs