Add gem with basic dependencies

The gem skeleton was created with bundler. Green shoes has been added as
a dependency via the github repository, as there is currently no version
on rubygems that works with main.

See issue #72 and pull request #73 on green shoes for the reason why.
Add executable file to run breaktime.rb

This is so that command `breaktime` is available after installing the
gem.
Add dialog for countdown to breaktime

The dialog uses green shoes for creating a GUI.
Tinker with rufus scheduler, executing the dialog
Remove random exit(3) from eof
Try using trollop instead of main for options

Currently only checking for switches.
Determine screensaver command based on OS/win manager

Also scheduling the break according to a YAML configuration file (or
sensible defaults). The user can choose days when breaktime will run,
and an interval at which it's run.
Refactor option parsing to separate class, add log4r
Use Log4r for logging and replace puts

The level of output can be specified with the --level parameter. Also
change 20 second warning to 10 second.
Change seconds to minutes for loop
Tidy up exception handling and process exec

Catch all known exceptions and display helpful error messages. Also, run
breaktime command with all current cli options.
Introduce logging to Command and LinuxWinManager classes
Add exit code definitions
Catch parse exceptions for configuration file
Add spermy operator to all gems in Gemfile

Currently the compatible green shoes version (1.1.373) can only be
gotten from the github repo. This will hopefully change soon.
Add detail to README file on usage and instructions
Update installation information in README
Introduce daemonizing with dante
Add fairly detailed comments
Add more detail to README regarding YAML config