Fix two issues with month command

The month command didn't previously work in December.  It didn't handle
the logic to understand that January (month 1) follows December (month
12)

Also it's not necessary to call Time#to_date in the month command.  This
method is private in ruby 1.8.6.  Removing this call provides some
additional level of compatibility running under 1.8.6.
Fix 1.8.7 compatibility in new tests
Version 1.8.5

* Fix - month command did not work in ruby 1.8.x
* Fix - month command did not work in December
Added spec for week command
Fixed f-d up month logic

I'm not sure why this had Chronic parsing "last February".  Just figure
out the first day of this month instead.
Version 1.8.6 - Ruby 2.0 compatibility

Getopt Declare uses a \255 byte for internal escaping which doesn't play
well with Ruby 2.0.  Use the ascii group sperator "\29" instead which
plays better with unicode.

Also vendor getopt since it doesn't seem to be maintained any longer.

Resolves #57
Issue #59 Adding "today" filter
Issue #60 Output to STDERR when no active task
Merge pull request #61 from keelerm84/today-filter

Issue #59 Adding "today" filter
Merge pull request #62 from keelerm84/t-now-command-when-not-on-task

Issue #60 Output to STDERR when no active task
Added Matthew Keeler to contributors
Version 1.8.7

* Added today command
* now command output to STDERR when no active task
Add completions for the `sheet` command
Merge branch 'autocomplete' of github.com:TSFoster/timetrap into autocomplete
Add autocomplete for d[isplay]
Remove archived sheets from zsh autocomplete
Add zsh completions for first argument of t