fix formatting of most recent "changes" line in NEWS
1.1.7: will be tagged as "sbcl-1.1.7"
Handle environment initialization better.

Don't fail with mysterious errors and memory faults on startup during
initialization of *default-pathname-defaults* when the current
directory contains undecodable characters or is deleted. Similarly
catch decoding errors for things like *runtime-pathname* and
*posix-argv*.
Turn the errors into warnings, and ensure that streams are initialized
and the error messages can be printed.