Final nestmates spec

[Dan Smith]

I've uploaded what I believe could be a final spec for nestmates, here:
http://cr.openjdk.java.net/~dlsmith/nestmates.html

Since October, changes include:

- Tweaks to the explanatory material in 2.11.8 and 3.7

- Some restructuring of the new 5.4.4 text to be a little less disruptive and more clearly define "same nest" and "nest host". There are some subtle behavioral differences compared to the previous iteration when errors occur.

- Added an example to 5.4.5 to illustrate transitive overriding

—Dan