Merge branch 'master' of https://github.com/datagovuk/ckanext-issues
[README][s]: change to markdown and a few tweaks.
[model,bugfix][xs]: import sqlalchemy stuff from sqlalchemy rather than ckan.model.meta (which no longer has the stuff).
[routes][xs]: get rid of trailing slash on routes (we redirect from trailing slash to no slash).
[README][s]: add some user docs (e.g. where urls are etc).
[#8,templates][m]: first pass on converting issues index and add page to jinja.
[#5][s]: remove obsolete tests.
[model][s]: various small-ish changes to model.

* add title attribute to issue
* change package_id to dataset_id on issue table
* tweak names of categories
[#9,#5,logic][m]: start work on a logic layer (issue create and show done) plus tests thereof.
[#9,#5,logic][s]: auth for show and create working.
[refactor][s]: remove old rest API as we will be providing action API going forward.
[controller][m]: refactor issue add to use logic system.

* Also put under test - see #9
* Also get rid of issue / issue category relationship for the present since we
  probably want something richer (like tags)
[fix][xs]: fix new issue link from issues page.
[#10,show][m]: basic issue show page working (with test).
[#11,comment][m]: issue comments in logic layer.
[model][s]: add status column to issue (open or closed).
[#11,comments][s]: new comment form on issue page.
[logic][s]: GET issue result dict includes comments.
[#11,comment][s]: comment creation reinstated on issue page.
[#10,show][s]: show comments on issue page.