Add aliases for timewarrior
Add aliases for timewarrior

Added shortcut aliases for timewarrior (1):

* `tw` = `tw summary` - Shortcut to show the summary.
* `tws` = `timew :ids` - Shortcut to show IDs by default
  (depends on `alias.tw`).

References:

  (1) https://taskwarrior.org/docs/timewarrior

Closes GH-127

arcticicestudio/igloo,arcticicestudio/igloo,arcticicestudio/igloo