The 'Beta Testing' tab should be first in plugin installer

[nacin]

If you're running a development build, we append a 'Beta Testing' tab where we list plugins which are features in development (#28513). We should make this tab primary for the purposes of discovery.

Looking for a few affirmative nods.

[helen]

As mentioned in IRC, I envision us someday getting to the point of "recommendations". In that line of thought, Beta Testing is like recommendations for people running dev builds. Can get behind it.

[kpdesign]

I think this is a good idea. +1 from me.

[johnbillion]

We should add a message to the top of this screen so it's clear what's being shown. Example:

"You are using a development version of WordPress. Below is a list of feature plugins which are also under development. Feel free to test them out and provide feedback [where?]."

[swissspidy]

Patch doesn't apply cleanly against trunk anymore. A message on top of the screen makes sense.

[swissspidy]

29631.2.diff​ is a refreshed patch that moves the 'Beta Testing' tab to the beginning and adds the following message to the top of the screen:

You are using a development version of WordPress. Below is a list of feature plugins which are also under development. ​Learn more.

I didn't add a link to provide feedback because there's no single way to do so and most feature plugins don't clearly state where to provide feedback either. Some readmes could be improved I guess :)

Moving to 4.5 for consideration.

[swissspidy]

Nacin suggested something along the lines of:

You are using a development version of WordPress. These feature plugins are also under development. <a href="%s">Learn more</a>.

@johnbillion Let me know what you think

[swissspidy]

29631.3.diff​ changes the sentence to:

You are using a development version of WordPress. These feature plugins are also under development. <a href="%s">Learn more</a>.

[swissspidy]

In 36297:

Plugins: Make sure the 'Beta testing' tab is first in the plugin installer.

This makes feature plugins more discoverable for people running development builds.

Fixes #29631.