Support for Other inputs types besides Text

The Problem: Co-Authors-Plus Guest-Authors Profiles are very limited. If you want to expand on a existing Group ("Constact Fields") You can only use Text input types.

The Solution: A field item called Input that declares the field's type. This would be assumed by default to be text, and the existing, "hidden", "email" and "website" fields would be assigned the standard "hidden", "email" and "url" input types. 

In addition, for someone who may not want to website field to be forced to a real URL, a filter would be applied to each field's input to allow it to be override, without pulling all fields via "coauthors_guest_author_fields" filter.

The new filter would look something like this `$pm_key_input`. So to change Website back to text would be `apply_filter('cap_website_input', 'myfunction_that_returns_text');`

Does not yet support:
Select
MultiSelect
Radio (Easily)

Adds Support for:
Checkbox
Url
Email
Number/date fields
Better Checkbox Support

Added Support For Checkboxes to save and show the correct info. After #123 this is now easily.
Fix for checkboxes
A basic Travis setup
Basic test cases for adding coauthors to a post
Modify the behavior of `add_coauthors()` such that a new author is actually appended.

Previously, the behavior would be whatever the behavior of `wp_set_post_terms()` was, which might ignore order.
Readme mention of unit tests
Merge pull request #178 from Automattic/basic-tests

Unit tests scaffold
When adding coauthors to a post, update the `post_author` if the original is no longer an author.
When tests fix a bug, let's add a note on the test for future reference.
Merge pull request #140 from Automattic/fix-140

add_coauthors should update post_author if append = false
Readme for #140
Update class-coauthors-guest-authors.php

Should Meet WordPress coding Standards now. Adjusted, filter names to prefix with CAP-, also they are section & field specific. 

Test of the filter and adding a new field (checkbox)
https://gist.github.com/alpha1/9421107

limitations:
radio buttons likely do not work.
select/multi select will not work.
Textareas do not work. 

Only inputs that are similar to a test field, like email will work. Checkboxes also work.

I'll be happy to work towards supporting all of those in the future.
Always run tests as multisite because we need to make sure author queries behave properly
More prep for multisite tests
Model core's behavior when determining whether the author archive should be displayed

The author archive should be displayed when the user is a member of the blog, or the user has a previously published post on the blog.

The author archive shouldn't ever be displayed when the user has no published posts on the blog.

See https://core.trac.wordpress.org/changeset/27290

Fixes #133, #169
Only try to reassign if the `$_POST['reassign']` is set.

Sadly, it's not actually passed through the action
Update readme for #159
Test state when user has been deleted.
Merge pull request #179 from Automattic/fix-author-queries

Fix behavior for author queries