[native-lang] OCA replaces SCA

Hi,

the Sun Contributor Agreement has been replaced with the Oracle 
Contributor Agreement.
  http://www.openoffice.org/licenses/oca.pdf
Besides the change of the company you sign the agreement with the 
content is the same. This also holds true for the exceptions for 
documentation and extensions which continue to be included in the form.

I updated the primary occurrence, the programming page in the 
contributing section, and will have a look at our Wiki now. If you 
stumble over other references please correct those too.

Greetings
Stefan