Emit one index statement per line

[pnorman]

By emitting one index statement per line and stripping any newlines out of the WHERE conditions, this allows use of our indexes with xargs, e.g.

scripts/indexes.py --fillfactor 100 | xargs -d'\n' -P20 -I_CREATE_ psql -Xqat -d flex -c "_CREATE_"

With newline changes, the above command will create up to 20 indexes in parallel.

Unknown: should this be standard or a command-line option? If a command-line option, should it use \0 instead, which allows use with xargs -0 instead of relying on GNU-specific behavior around quotes and -d?