Stop paging listings after page 99

[StevenMaude]

With a page size of 100, the API won't return results for page
100, page 99 is the last valid one.

Known issue: http://developer.zoopla.com/forum/read/162309

[StevenMaude]

This arose because Zoopla were giving out seemingly bad results. For a particular postcode search, the first page of results had only 99 entries, instead of 100. Subsequent pages had the correct number of entries, but this meant that the number found was one lower than the expected result count.

Once the code reached page 100, it errored. Really, this shouldn't happen unless you're doing a big search (the example in the Zoopla forum was searching for properties in London).

[bendholmes]

This should be >= 100 if for example someone picks a specific page number > 100 rather than simply incrementing.