rels #80. fix for reference rdf converter
Merge pull request #81 from sysoev-a/issue80

rels #80. fix for reference rdf converter
change .equals(null) to == null
Merge pull request #83 from Wikidata/bug-fix_WikidataPropertyType

change .equals(null) to == null
Use temporary files during download

This prevents unfinished files from lying around when downloads are
interrupted.
Small fix in RDF serialization example
Simpler ways for iterating over WDTK data

* Classes that are mainly collections of other objects implement
Iterable (e.g., Reference).
* Classes that have nested collections of objects provide direct
iterator access to all elements (e.g., to iterate over all statements in
an item document).
* A helper class NestedIterator is used to iterate over nested
collections.
Add dependency to wdtk-util to use NestedIterator
Update RELEASE-NOTES.md
Merge pull request #86 from Wikidata/partial-dump-downloads

Partial dump downloads
patch some javadoc warnings
Merge pull request #92 from Wikidata/javadoc-fixes

patch some javadoc warnings
Merge branch 'master' into iterable-data

Conflicts:
	RELEASE-NOTES.md
Fix buffer size computation
Merge pull request #88 from Wikidata/iterable-data

Simpler ways for iterating over WDTK data
Change "base IRI" of entity id values to "site IRI"

* Site IRI is the same string as before, but now interpreted as an
identifier for the site the entity comes from.
* A new getter makes this string retrievable (extended interface of
EntityIDValue).

This is necessary to ensure that one can construct new ItenIdValues and
PropertyIdValues from the information that one can get from an object of
this type. The re-interpretation of "base IRI" as "site IRI" is to
prepare for future Wikibase changes where entities may have different
IDs and different ways of constructing IRIs (e.g., Commons file name IDs
and URL-encoding as part of IRI construction).
Merge pull request #93 from Wikidata/entity-baseiri

Change "base IRI" of entity id values to "site IRI"
Standard implementations for hashCode(), equals(), and toString()

These new static methods can be used for arbitrary implementations of
the WDTK data model. They evaluate object based on their interfaces
only. This makes it easier and cleaner to introduce additional
implementations for WDTK interfaces.
Static methods for creating WDTK objects

We don't really need a factory in most cases. Moreover, this code has
some convenience methods that make it easier to create data objects for
common default values. In the future, it might also support
builder-style object creation for some of the classes.
Updated test files to match new hash codes