Basic author filtering

[ninjaprawn]

Author Filtering:

• When searching for packages, you can add an author filter (currently only the filter allowed, no keywords in addition). Do this by adding "Author: " to the beginning of your query (include space). For performance reasons the filter is only run when the search button is pressed.
• This filters like a normal search query: It goes through every package and checks the author.

If this works out, we can "easily" add a "More by this author" button to the package page

Part 1/Possibly 2 of #36

[JohnCoates]

Looks good. Left a comment that might improve readability for the future.