strip ampersands from Scopus search queries

Treats ampersands the same way percent-signs were already being treated: replace them with a space character.
After testing:
* doing the star/question-mark trick didn't work -- i.e. {&} is invalid on a query string
* the following all produced the same results, based on the original string "X+R&D+Y": "X+R+D+Y", "X+RD+Y", "X+Y"; so I went with the one that already existed in code