Removed unused variable.

* The argspec was retrieved every time an API command was called even
  though the APICall object has it stored already.
Improved logging messages for #156.

* Fixes #156.
Improved error messages for bad time conversion.

* Within the API client.
Improved error message for #165.

* User is now prompted to try again which has worked every time I've
  encountered the bug.
Merge branch 'master' into v0.2dev