Merge pull request #971 from holu/master

[FIX] FTBFS with Java 8: reference to Base64 is ambiguous
[MOD] Numerous rewritings, optimizations, bug fixes
[FIX] XML Parsing: use default XML parsing in more cases
[FIX] XQuery, file:write: materialize result before writing it
[MOD] XQuery: unknown function: show similar function names
[FIX] Core: File-system locks revised
[MOD] XQuery: better cost estimation for range queries
[FIX] XQuery, Unit Module. Closes #974.
[FIX] XQuery, Unit Module. Closes #974.
[MIN] Merged with stable branch
[MIN] XQuery: minor refactorings
[FIX] GUI: correct rendering of database info panels
[MOD] XQuery: bind data reference to variables
[MIN] Property files updated.
[ADD] Indexing: recreate index in main-memory DB. Closes #975
[MIN] Formatting
[MOD] CSV Parsing: using input stream. Closes #976
[MIN] XQuery: minor rewritings
[MIN] Minor rewritings
[MOD] CSV Parsing: Slightly reduced memory consumption. #976