Add Incubation DISCLAIMER.

DISCLAIMER

+Apache OpenOffice is an effort undergoing incubation at The Apache 
+Software Foundation (ASF), sponsored by the name of Apache Incubator. 
+Incubation is required of all newly accepted projects until a further 
+review indicates that the infrastructure, communications, and decision 
+making process have stabilized in a manner consistent with other 
+successful ASF projects. While incubation status is not necessarily a 
+reflection of the completeness or stability of the code, it does indicate 
+that the project has yet to be fully endorsed by the ASF.
+