Slightly improves code readability 

- Tidying proc comments.
- set lorem "$lorem ipsum dolor" → append lorem " ipsum dolor"
- build query string with ?[http::formatQuery {*}$params_dict]
- every n minutes (when 60 % n == 0): bind time */n * * * *
add COPYING file
convert readme to markdown
move changelog and usage information into separate files

this is instead of having these in the script headers themselves
split some functionality out of twitter.tcl into a library

as well:
  * test_oauth.tcl is now cleaner and more usable
  * add twitter_poll.tcl, a script to pull updates into a postgres database
  * minor documentation and style improvements in general
add optional polling of mentions timeline
fix the followers and following triggers