Check error handlers for specific classes first

This allows adding error handlers like this:

    @app.errorhandler(werkzeug.exceptions.Forbidden)

And subclassing HTTPExceptions:

    class ForbiddenBecauseReason(Forbidden): pass

    @app.errorhandler(ForbiddenBecauseReason)
    def error1(): return "Forbidden because reason", 403
    @app.errorhandler(403)
    def error2(): return "Forbidden", 403

... the idea being, that a flask extension might want to raise an
exception, with the default behaviour of creating a HTTP error page,
but still allowing the user to add a view/handler specific to that
exception (e.g., "Forbidden because you are not in the right group").
Fix import in viewdecorators.rst for @templated
Tweak wording in viewdecorators.rst
Fix typos in docstrings and comments in run.py
Check links in the documentation with tox
Fix Pocoo documentation links
Link to https version of python docs

To which the http version permanently redirects
Fix Jinja link
Switch pypi links to https

To which the http version redirects permanently
Switch packages.python.org to pythonhosted.org
Use https instead of http for docs.python.org
Use https for devcenter.heroku.com
Use libevent.org
Switch diveintohtml5.org to diveintohtml5.info
Run tests with Python 3.4 with tox
Merge pull request #1032 from cgar/spelling

few mispelling errors
Merge pull request #1030 from zakj/master

Fix typos in docstrings and comments in run.py
Depend on click now
Added click support to Flask
Added changelog entry for click