Return consistent number of items per search results page

[kerchner]

Launchpad collapses multiple holdings for the same item into single launchpad results - I assume this is in cases where the identical item (separate catalog records) is available at >=2 libraries.

This is causing the launchpad results page to often provide inconsistent numbers of results - for the current default of 20 results per page, < 20 results - example: http://findit.library.gwu.edu/search?q=architecture which returns 16 results (for what appears to be 21? holdings).

For launchpad itself, this is probably a minor annoyance that few will notice, especially before #855 is implemented. However, implementation of https://github.com/gwu-libraries/obento/issues/233 (depends on #855) will ask the launchpad API for the first 3 results. A search like q=architecture, yields only 2 results. A short-term fix might be for obento to ask for, let's say, the first 6 results (really, holdings), but only show the top 3 - with no change to launchpad.

Look at the feasibility of a more robust fix for this issue, so that the API always provides the requested number of items (not holdings) per page.