See: http://stackoverflow.com/questions/218156/bash-regex-with-quotes

- 'add' and 'addm' now 'addto' with $TODO_FILE instead of user supplied file

- 'addto' now shows the capitalized filename in place of 'TODO:'.
  For example, adding to garden.txt produces a output prefixed by 'GARDEN:'
  (Probably the most controversial part of this commit and up for
  discussion. If kept, the 'listfile' output should be made to match.
  Note that this convention would then minimize standard output by
  dropping the file name.)

- All existing add/addm/add-date tests pass. Two new test sequences were
  added to test 'addto' and 'listfile' functionality.

- A space/tab nuissance was cleared up in the tests/README file.

- _list() now shows the capitalized filename in place of 'TODO:'.
  For example, listing garden.txt produces a output prefixed by 'GARDEN:'
  This eliminates the ' from $FILE' part of the _list() output. All tests
  were adjusted to match this new output.

Versions of bash before 3.0 do not have =~ syntax to match on a regex.
Changed to using a simple grep -c test instead.
Fixes issues with osx and Solaris 9 and before.