[loc-en-dev] Updated JavaDoc

[Yoshito Umaoka]

http://sites.google.com/site/openjdklocale/apis

I updated the JavaDoc based on things found during the implementation 
and some inputs from Doug.

- Locale.LocaleExtension / Locale.LocaleKeywords are gone.
- Setters in LocaleBuilder no longer throw an exception for a malformed 
input.
- LocaleBuilder#create() - ignore malformed fields.
- LocaleBuilder#createStrict() - return null when any malformed fields 
are found.

-Yoshito