Added additional random parameters 

Added random_cat_id and random_post_type parameters to match the functionality of the original Random Redirects plugin.
Speed: Abstract out function call.

Previously ran 30x for a 23ms hit in vvv, let’s abstract it out to only
run once.
Added additional random parameters Fixes #867

Made changes as per @enejb's comments.
Uses https for reddit sharing links as appropriate

Made two small changes to the Share_Reddit class to use the
http() method to use the appropriate prefix for the reddit sharing
URLs.
Remove a `file_exists` check.

This is called about 44 times in a front-end request, adding about 33ms
on the load time.  We shouldn’t ever be calling get_module() on
something that doesn’t exist anyway, so a Warning being generated by
the `fopen` inside `get_file_data` is fine (and probably useful, as it
will no longer fail silently)
Speed: cache available modules in an option

The cache is invalidated:

- when Jetpack is updated
- when an admin page is loaded

It's disabled for admin pages and in development mode
Removed unused network.css files
Jetpack: Cache file_data in an option.

And index it by version.

This saves about 105 ms (it had been less previously, but when we
removed the prior `file_exists` checks, the `fopen` calls in
`get_file_data` went up.)

This does mean that we’ll probably need some sort of way to turn this
off when in active development, so changes we make to the module
headers actually get seen.  Maybe compare it on the admin side to the
real headers if `?page=jetpack` — unsure.
Jetpack_Options: Pass $default to get_option

If non-compressed.
Jetpack_Options: Pass $default to get_option

If non-compressed.
Adding three tests to class.jetpack for sort_modules

The main Jetpack class was very lightly tested, so this
commit adds three tests covering the sort_modules class method,
which is both simple and would cause trouble if unintentionally
changed. I did not include a @since tag as I do not know when the
method was introduced.
Merge pull request #959 from enkrates/add-tests-to-jetpack-class

Adding three tests to class.jetpack for sort_modules
Merge pull request #877 from iannuttall/master

Added additional random parameters
Merge pull request #951 from enkrates/allow-reddit-sharing-to-use-ssl-link

Uses https for reddit sharing links as appropriate
Minor refactor of caching available modules.

Old way we were purging the option on plugin update, this way, we’re
basically updating it if it’s changed on every admin view.

We’re also storing it in an array key of the option, so versions never
cross the streams.
Whitespace aligning.
Refresh the file_data cache on JP admin pages
Deleted jetpack.css
Speed: Abstract out function call.

Previously ran 30x for a 23ms hit in vvv, let’s abstract it out to only
run once.
Remove a `file_exists` check.

This is called about 44 times in a front-end request, adding about 33ms
on the load time.  We shouldn’t ever be calling get_module() on
something that doesn’t exist anyway, so a Warning being generated by
the `fopen` inside `get_file_data` is fine (and probably useful, as it
will no longer fail silently)