RFR: JDK-8205418: Assorted improvements to source code model

[Jan Lahoda]

Hi,

I'd like to propose a few improvements to the source code model as seen 
through the com.sun.source APIs.

The changes include better error recovery, a fix end positions, and a 
fix for Trees.getScope when used with a TreePath that point to a block 
of a lambda expression, including cases where there's an error in the 
source code.

Bug: https://bugs.openjdk.java.net/browse/JDK-8205418
Webrev: http://cr.openjdk.java.net/~jlahoda/8205418/webrev.00/

How does this look?

Thanks,
    Jan