Added callback handler support for before_tick, after_tick, before_run, after_run.
Merge pull request #30 from marclennox/callback_handlers

Added callback handler support
Add callback tests
Fix duplicated test names
Version 0.6.1

Changes:

  Support wildcard for minutes of `at` option (by @mizoR)

  Add before_tick, after_tick, before_run, after_run callbacks (by @marclennox)
point to rufus-scheduler github page

was pointing to old rdoc
Merge pull request #56 from jmettraux/master

point to rufus-scheduler github page
Add description of :at's day of week specification

According to #57
support for error/exception callback
Memoize error handler
Add test for error_handler
Merge branch 'error_handler'
Add description of error_handler
Version 0.6.2

Changes:

   Fix readme (by @jmettraux and @avokhmin)

   Add error_handler feature (by @aurels)
add --dir option to change Dir.cwd

Fixes #60
allow relative directores for --dir
automatically set Dir.cwd after forking a new process
fix Dir.pwd typo
Set current_dir option by -d or --dir
manager class_variable move to singleton_variable

- Clockwork module define in manager class_variable.
  but, class_variable is all object shared.
  was avoiding collision by moving to singleton instance.