Fixes #13 - verbose listing tasks errors

Had extra substitution variable that was unused when printing the results.
Merge remote-tracking branch 'upstream/master'

Bringing in updates from @drobertadams master
Resolves #4 - clients displayed with projects

* adds new command `clients` which lists clients
* includes the client when listing the project. And does it with only one additional API call unlike, how I did it with projects. This was a learning exercise so that I could fix issue #10
Fixes #10 - performance improvement listing time entries

Previously, was making a separate API call to look up the project during each print_time_entries. Now moved to making the project call at the same time as the time_entry call and matching the time entries project id to the project when building the entry to print.

Time tests

I have 8 time entries in my current dataset. So, for each one it has to call the projects API in the prior version.

Prior version elapsed time: 9.55 seconds
New version elapsed time: 2.42 seconds
Previous commit broke now function

By adding the project name to the print_time_entry function, I also needed to add that to the list_current_time_entry function.
Merge pull request #4 from beauraines/master

Bug fix, add client listing and performance improvement