Problem:    The terminal API "drop" command doesn't support options.
Solution:   Implement the options.

Problem:    Capitalize argument not available in long form.
Solution:   Recognize -capitalize.  Update man page.

Problem:    Cannot filter :ls output for terminal buffers.
Solution:   Add flags for terminal buffers. (Marcin Szamotulski, closes #2751)

Problem:    Too many #ifdefs.
Solution:   Graduate FEAT_LISTCMDS, no reason to leave out buffer commands.

Problem:    No completion for argument list commands.
Solution:   Add arglist completion. (Yegappan Lakshmanan, closes #2706)

Problem:    Terminal API may call a function not meant to be called by this
            API.
Solution:   Require the function to start with Tapi_.

Problem:    Job in terminal can't communicate with Vim.
Solution:   Add the terminal API.

Problem:    Trimming white space is not that easy.
Solution:   Add the trim() function. (Bukn, closes #1280)