Port: Search.TopTermsRewrite

added PriorityQueue implementation to Support namespace. also, some
small fixes in fst classes
Port: more search classes

TermCollectingRewrite, MultiTermQuery, NGramPhraseQuery
Merge remote-tracking branch 'upstream/lucene_4_3_0' into lucene_4_3_0
Port: NRTManager, added Support.TimeUnit
Merge remote-tracking branch 'upstream/lucene_4_3_0' into lucene_4_3_0
Port: commit csproj
Merge remote-tracking branch 'jamesblair/lucene_4_3_0' into lucene_4_3_0