fix interference of unboxing inference for different arguments
Support SO_REUSEADDR on (udp-bind!), for multicast use.
UDP Multicast primitives and documentation.
Make xform build step work in Windows builds
bump version number
reference: adjust docs for UDP multicast

Minor style changes to better match the rest of the docs,
plus "HISTORY.txt" entry.
reference: fix grammar for cross-phase expressions
doc search: fix mismatch between generator and renderer

This change revisits commit eb7fa6f066. I think the problem
is not in the rendering of index entries but on the generation
side. The generator was converting Xexprs to strings, except
that strings were left as-is, which is inconsistent. So,
I've reverted commit eb7fa6f066 and fixed the generator.