Add easy way to use FastHttpLocust

[LRAbbade]

Description of issue

Using the FastHttpLocust right now is complicated and lacking documentation.

Expected behavior

from locust import FastHttpLocust
print('happiness is a warm gun')

Actual behavior

cannot import name 'FastHttpLocust' from 'locust'

Environment settings

• OS: macOS 10.14.4
• Python version: 3.7
• Locust version: 0.11.0

Steps to reproduce (for bug reports)

from locust import FastHttpLocust

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That's pretty self explanatory. I just want an easy way to use the FastHttpLocust, I saw some people talking about it in the issues, and it seems to be very good for my situation, but honestly, I don't want (and neither have the time) to go through the trouble of cloning the specific branch, understanding the code (which has no documentation right now) and using it. I just want to import it differently and be on my way.

Make it happen please.

[cgoldberg]

I just want to import it differently and be on my way.

go ahead and submit a PR to make that happen. If you require a higher level of support, it doesn't currently exist.