README.md: Add MAVEN_OPTS to deal with out-of-memory
SolrFullAnswerProducer: Tiny cleanup
SolrFullPrimarySearch: Log also the result score/relevance
Make sure lemmas are always lowercased before processing

Current lemmatization doesn't always yield lowercase strings even though
that ought to have been the case in the past. That breaks mainly when
analyzing the first word of a question (how, where, ...).
Solr: New interface runIDQuery() for fetching specific pageIDs

(Used in later commits.)
cz.brmlab.yodaqa.provider.rdf: New module, class DBpediaTitles

DBpedia SPARQL interface using Apache Jena.  The DBpediaTitles class
allows a simple query for precise article title matches (something
that solr itself unphantomably doesn't appear to be able to do...).

Includes some abstraction (that pretends to be caching though it isn't)
that allows extension to other DBpedia queries.

(DBpediaTitles class will be used in later commits.)
DBpediaTitles: SPARQL is case-sensitive, capitalize first letters
ClueConcept, CluesToConcepts: New annotation and annotator

The ClueConcept annotation is generated from CluePhrase and ClueNE
annotations if they correspond to wikipedia article titles, substituting
for these and all their sub-clues.

This partially fulfills the #wikipieces item from recent performance
analysis.
DBpediaTitles: Add some debug prints
SolrFullPrimarySearch: Also directly retrieve ClueConcept wiki articles

It turns out that sometimes, these would never be fetched; especially
useful since we are following redirects when generating ClueConcepts.

This fulfills the remaining part of #wikipieces.
Clue: Add a label feature; use getLabel() inst. of getCoveredText()

Useful for concepts, later for abbreviations; clue may be related but
not equal to the covered text.
CluesToConcepts: Get concepts even for the short ClueTokens
CluesToConcepts: Don't remove original clue in case of different label