Feature: issue creation

This is a first version of issue creation functionality, which is:

- adding plumbing `issues create` command;

- adding porcelain `jcr (blueprint|subtask)` command;

- allows creating issues of different types;

- also requests required fields even if those are not listed by
  the current template;

- can link Sub-tasks to parents (parent's issue key should be provided
  in required "Parent" field);

- only supports editor-based issue creation for now (with -e switch).

Signed-off-by: Serge Broslavsky <serge.broslavsky@linaro.org>
Documentation: updated `man jic` (WIP)

Contains more of the documentation now. Still not complete.

Signed-off-by: Serge Broslavsky <serge.broslavsky@linaro.org>
New version: v14.45.1

Signed-off-by: Serge Broslavsky <serge.broslavsky@linaro.org>