Version 0.5.0

This is the first stable 0.5.x series. ChangeLog:

* Ability to override existing keywords; in this case, all previous existing
  syntax checkers/keyword validators will be overriden.
* Ability to unregister existing keywords.
* Natively supported URI schemes now include "file", "ftp" and "jar" along with
  "http".
* Ability to unregister downloaders for existing schemes.
* Ability to add a default URI namespace for JSON Reference resolution: if a
  JSON Reference is relative, and the current schema does not have an absolute
  id, references will resolve against the defined namespace.
* Ability to set URI redirections: this allows to silently redirect potentially
  unreachable Internet resources to locally available mirrors.
* JSON Pointer now complies to draft v3 (was draft v1).
* Lots of JavaDoc improvements.

Francis Galiegue (58):
      Make JsonValidator an abstract class
      SelfValidationTest: create a DataProvider for Google schemas
      SchemaNode: move to the validator package
      README.markdown updates
      SchemaRegistry: add the notion of namespace
      JsonSchemaFactory: allow to set the schema namespace
      SchemaRegistryTest: add another test
      Javadoc: overview.html update
      Fix Javadoc error...
      KeywordValidator: add first infrastructure elements for better reporting
      Implement .toString() for AbstractTypeKeywordValidator
      Implement .toString for additional{Items,Properties} validators
      DependenciesKeywordValidator: implement .toString()
      NumericKeywordValidator: implement .toString()
      .toString() for {Enum,Extends,Format}KeywordValidator
      KeywordValidator: make .toString() abstract, make all inheritors comply
      URIManager: improve one error message
      Rename HTTPURIDownloader to DefaultURIDownloader, add supported schemes
      SchemaContainer and SchemaNode: unimplement equals()/hashCode()
      Inspections run: some code cleanup
      Some minor code style nitpicks
      URIManager: allow override of an already existing scheme downloader
      URIManager: add ability to unregister a scheme
      JsonSchemaFactory: add ability to unregister a scheme
      KeywordBundle: allow overriding an existing keyword
      KeywordBundle: return the list of syntax checkers directly
      KeywordBundle: return the list of keyword validators directly
      KeywordBundle: fix bug with new registration mechanism
      KeywordBundle: make it stop to implement Iterable, remove keywords map
      Rewrite tests for KeywordBundle
      SchemaRegistry: add javadoc
      KeywordBundle: update javadoc
      JsonSchemaFactory: add ability to unregister a schema keyword
      Add some more javadoc, fix a missing link
      Remove a lot of now unused test files
      JsonPointer: don't make the string representation hash-prefixed
      JsonRef, JsonFragment: avoid building from a null URI fragment
      JsonFragment.EMPTY, IdFragment: .toString() should not be hash-prefixed
      JsonRef: add Javadoc
      New JSON Pointer IETF Draft text
      Make a JSON Pointer test file
      Update JSON Pointer implementation to draft 3
      JsonPointer: add invalid pointer detection tests
      JsonPointer: be more explicit when a malformed pointer is encountered
      Minor code style nitpick...
      Javadoc updates
      One minor code style nitpick
      Remove json-schema.org mirror
      Miscellaneous fixes (Javadoc mostly)
      README.markdown: add links to the relevant IETF drafts
      README.markdown: add a link to the existing javadoc site
      URIManager: mention the nice property of ObjectMapper's .readTree()
      Major javadoc updates
      Javadoc's overview.html update
      pom.xml: next version will be 0.5.0
      Remove dependencies on slf4j/logback
      URIManager: implement schema URI redirection
      JsonSchemaFactory: allow to set a URI redirection

Signed-off-by: Francis Galiegue <fgaliegue@gmail.com>