General
  * License changed from Apache 2.0 to New BSD.
  * It is now possible to define custom "options", which are basically
    annotations which may be placed on definitions in a .proto file.
    For example, you might define a field option called "foo" like so:
      import "google/protobuf/descriptor.proto"
      extend google.protobuf.FieldOptions {
        optional string foo = 12345;
      }
    Then you annotate a field using the "foo" option:
      message MyMessage {
        optional int32 some_field = 1 [(foo) = "bar"]
      }
    The value of this option is then visible via the message's
    Descriptor:
      const FieldDescriptor* field =
        MyMessage::descriptor()->FindFieldByName("some_field");
      assert(field->options().GetExtension(foo) == "bar");
    This feature has been implemented and tested in C++ and Java.
    Other languages may or may not need to do extra work to support
    custom options, depending on how they construct descriptors.

  C++
  * Fixed some GCC warnings that only occur when using -pedantic.
  * Improved static initialization code, making ordering more
    predictable among other things.
  * TextFormat will no longer accept messages which contain multiple
    instances of a singular field.  Previously, the latter instance
    would overwrite the former.
  * Now works on systems that don't have hash_map.

  Python
  * Strings now use the "unicode" type rather than the "str" type.
    String fields may still be assigned ASCII "str" values; they will
    automatically be converted.
  * Adding a property to an object representing a repeated field now
    raises an exception.  For example:
      # No longer works (and never should have).
      message.some_repeated_field.foo = 1

Also, update version numbers to 2.0.2-SNAPSHOT.

Protoc (parser)
- Improved error message when an enum value's name conflicts with another
  symbol defined in the enum type's scope, e.g. if two enum types declared
  in the same scope have values with the same name.  This is disallowed for
  compatibility with C++, but this wasn't clear from the error.
C++
- Restored the set_foo(const char*) accessor for "bytes" type because some
  code inside Google depends on it.  However, set_foo(const char*, int) is
  still there (and actually is changed to take const void*).
- Fixed TokenizerTest when compiling with -DNDEBUG on Linux.
- Other irrelevant tweaks.
Java
- Fixed UnknownFieldSet's parsing of varints larger than 32 bits.
- Fixed TextFormat's parsing of "inf" and "nan".
- Fixed TextFormat's parsing of comments.
Python
- Fixed text_format_test on Windows where floating-point exponents sometimes
  contain extra zeros.

- Improved readmes.
- Fixed incorrect definition of kint32min.
- Fixed absolute output paths on Windows.
- Added info to Java POM that will be required when we upload the
  package to a Maven repo.