Fixed issue with adding rake task list twice

Improve compatibility with older tty-prompt v0.21.0 by setting select…

… choices via block argument when using a block

v0.2.0 changes:

- Optimized performance for JRuby
- rakeui, raketui, jrakeui, and jraketui shorter alternative commands
- Enter arguments when a rake task needs them
- Added an API for direct Ruby use
- Specify/limit tasks displayed

Regenerate gemspec for version 0.1.1

Initial v0.1.0 rake-tui implementation