Bug fix for 'reservoir' '$' query notation.

I failed to notice that the '=' character is a reserved character
in the '$' query notation. It is used to constrain the result
of the query, ie. '<', '=', or '>' can be used. I've fixed the
'$' notation in the reservoir data attachment to use '||' instead
of '='.
Merge pull request #128 from addthis/spiegel/reservoir-queryfix

Bug fix for 'reservoir' '$' query notation.