Series import: filter out invalid candidates

[php-coder]

We should filter out candidates with short names because otherwise they can match when we'll use LIKE and leads to a wrong category:

r.m.w.s.SeriesInfoExtractorServiceImpl   : Determining category from a fragment: 'ДАГОМЕЯ ? М? ДОИСТОРИЧЕСКАЯ ФАУНА ДИНОЗАВРЫ АВИАПОЧТА 3 БЕЗЗУБЦОВЫЕ МАРКИ С ПОЛЯМИ КУПИТЬ! (39)'
r.m.w.s.SeriesInfoExtractorServiceImpl   : Possible candidates: [С, М?, ФАУНА, (39), 3, БЕЗЗУБЦОВЫЕ, ПОЛЯМИ, ДОИСТОРИЧЕСКАЯ, ДИНОЗАВРЫ, МАРКИ, АВИАПОЧТА, ДАГОМЕЯ, ?, КУПИТЬ!]
r.m.w.s.SeriesInfoExtractorServiceImpl   : Found categories: []
r.m.w.s.SeriesInfoExtractorServiceImpl   : Possible candidate: 'С%'
r.m.w.s.SeriesInfoExtractorServiceImpl   : Found categories: [2]

The result is wrong because 2 is id of the Sport category, while I expect that it should found "Prehistoric animals" category.

Also let's filter out candidates with long names.

Perhaps, after fixing #819 it will find "Prehistoric animals" category from the first attempt (via aliases) and won't produce wrong result (because it won't do lookup with LIKE).