Log out activities

[searls]

Suture should log out when it's called and records something:

[<time>] Suture recorded a call to on your :foo seam to the :old path with arguments [1, 2, 3] and result 6

Can be configured by Suture.config (see #25) or ENV vars, but unlike other options, can't be set on a per-suture/verify basis b/c the logger is going to be a singleton (just to prevent config & reference leaking of Plan and TestPlan models further, esp. when logging in the absence of one)

Settings:

Suture.config({
  :log_level => "INFO",
  :log_file => nil,
  :log_stdout => true
})

SUTURE_LOG_LEVEL, SUTURE_LOG_FILE, and SUTURE_LOG_STDOUT should also work.