Enforce pep-8

We previously decided to adhere to pep8, but did not reformat all code
to comply, nor did we set up any tests to enforce this.

This reformats code to adhere to pep8 and sets up enforcement through
Tracis-CI.
Update bundled copy of Rocket

Fixes #268
Update bundled copy of Rocket (again)
Merge pull request #267 from zoni/pep8

Enforce pep-8
Merge pull request #270 from zoni/issue/268

Update bundled copy of Rocket
Docs: Add last_updated timestamp
Docs: Add previous and next links after main content
Docs: Rewrite plugin development guide
Fix sporadic test failure in test_plugin_cycle

Triggered by plugin installation taking longer than the timeout on
popMessage()
Fix make_ssl_certificate on Python 2

Fixes the following exception:

Traceback (most recent call last):

File "/home/travis/build/zoni/err/errbot/backends/base.py", line 520, in
_execute_and_send

for reply in replies:

    File "/home/travis/build/zoni/err/errbot/builtins/webserver.py",
    line 185, in generate_certificate

    make_ssl_certificate(key_path=key_path, cert_path=cert_path)

    File "/home/travis/build/zoni/err/errbot/builtins/webserver.py",
    line 58, in make_ssl_certificate

    cert.sign(pkey, u'sha256')

    File "build/bdist.linux-x86_64/egg/OpenSSL/crypto.py", line 827, in
    sign

    evp_md = _lib.EVP_get_digestbyname(_byte_string(digest))

    TypeError: initializer for ctype 'char *' must be a str or list or
    tuple, not unicode
Test Python 3.4 with Travis as well

Err supports Python 3.3+, so best to test all Python versions Travis
supports, just in case there is ever a difference between the various
3.x versions that causes incompatibilities.
Add requirements-development.txt

This makes it easy to install all development-related packages without
having to specify them manually in multiple places.
Call pep8 directly from run_tests.py
Update .gitignore
Exclude ./build from pep8 checks
Docs: Also autodoc __init__ methods
Allow webserver_webhook_test to be run parallel

It was working previously because of the order of tests coincidentally
configuring this plugin in an earlier-run test.
Split bot logic out of FullStackTest
Add additional FullStackTest documentation
Reorder testbackend imports