[stellation-res] checkin: add OS check re fileInfo, equals for artifact

[Dave Shields <shields@xxxxxxxxxxxxxx>]

Here are some of the recent bits and pieces. Nothing urgent, but I wanted to make
available the OS checks that, as Jonathan noted, hadn't yet been checked in:

Add code to test current operating system before invoking
Unix-specifix code.

Minor change to informative message to distinguish single
and plural case when listing number of merge conflicts.

Fix problems processing --revision option.

Use equals() when comparing artifact identifiers.

dave

-- 
Dave Shields, IBM Research, shields@xxxxxxxxxxxxxx.