bliptv: Pages start at 1

Page number already starts at 1 when invoking grl_paging_translate(), so no
need to increase it (else, it would start at 2).
bliptv: Allow operations requiring more than 1 page

Blip.tv handles results in pages of 100 elements.

So far, search/browse operation was working fine while the results were all of
them inside one page; if they required more than one page, only the results in
the first page were returned.

This commit fixes this problem, so now all the available results, no matter in
which pages they are, are returned.
bliptv: Check for no search results

When performing a search, and no results are found, instead of getting an empty
result dataset, Blip.tv returns just one "virtual" element telling there are
not results.

This commit checks for this case, and returns no results in case of matching
it.
bliptv: Add testsuite