New Timer utility for measuring CPU and wall times

Includes thread-aware timer registry for time
taking across multiple threads.
Added a first rough draft of the JSON parser for dumpfiles. Still work
in progress.

NOTE that the parser will introduce a new Maven dependency towards
"org.json"
Modified tests to be more robust (esp. on OpenJDK6)

Unfortunately, time measurements are somewhat random
and cannot be predicted very well. The tests could still
fail randomly if some very unusual runtimes occur.
Added further helper methods for the JSON parser.
Improved documentation.
=== Refactoring ===
Renamed JsonParser to JsonConverter since it represents better what the
class actually does.
Renamed variables to better represent, what they contain.

=== Assertions ===
Removed unneccesary assertions.
Added missing assertions.

=== Code general ===
Added further Methods so at least the top-level converting is complete.
Finer granularity is still work in progress.

=== Documentation ===
Added and improved documentation.
Changed the getDescriptions()-method to be consistent with the exception
handling of other methods.
Also added documentation.
Fix copy constructor of default implementation of bit vector
Create default implementation of ranked bit vector.

This class has 'rank' implemented (method 'countBits').
Added a first rough draft of the JSON parser for dumpfiles. Still work
in progress.

NOTE that the parser will introduce a new Maven dependency towards
"org.json"
Added further helper methods for the JSON parser.
Improved documentation.
=== Refactoring ===
Renamed JsonParser to JsonConverter since it represents better what the
class actually does.
Renamed variables to better represent, what they contain.

=== Assertions ===
Removed unneccesary assertions.
Added missing assertions.

=== Code general ===
Added further Methods so at least the top-level converting is complete.
Finer granularity is still work in progress.

=== Documentation ===
Added and improved documentation.
Changed the getDescriptions()-method to be consistent with the exception
handling of other methods.
Also added documentation.
Merge branch 'jsonToDataModel' of https://github.com/Wikidata/Wikidata-Toolkit.git into jsonToDataModel
Changed data types and implementations to accommodate for the changed
data model.
Added outline for the statements conversion. Still work in progress.
Added a first rough draft of the JSON parser for dumpfiles. Still work
in progress.

NOTE that the parser will introduce a new Maven dependency towards
"org.json"
Added further helper methods for the JSON parser.
Improved documentation.
=== Refactoring ===
Renamed JsonParser to JsonConverter since it represents better what the
class actually does.
Renamed variables to better represent, what they contain.

=== Assertions ===
Removed unneccesary assertions.
Added missing assertions.

=== Code general ===
Added further Methods so at least the top-level converting is complete.
Finer granularity is still work in progress.

=== Documentation ===
Added and improved documentation.
Changed the getDescriptions()-method to be consistent with the exception
handling of other methods.
Also added documentation.
Added a first rough draft of the JSON parser for dumpfiles. Still work
in progress.

NOTE that the parser will introduce a new Maven dependency towards
"org.json"