Replace EMPTY in SnowballStopFilter.
Replace EMPTY in SnowballStopFilter.

Using individual empty strings as hash values on construction is
wasteful, since all we care about is whether the key exists.  However,
it is more common to create SnowballStopFilter objects via
SnowballStopFilter#Load, and that uses individual empty strings anyway.
The whole Dump/Load mechanism should be overhauled the next time we feel
like bumping the index format.


git-svn-id: 33c1020af00f61ce75d0fe36814d3322ab23371a@1325065 13f79535-47bb-0310-9956-ffa450edef68

apache/lucy,kidaa/lucy,rbevers/lucy,pombredanne/apache-lucy,kidaa/lucy,nwellnhof/lucy,kidaa/lucy,kidaa/lucy,apache/lucy,nwellnhof/lucy,rbevers/lucy,rectang/lucy,kidaa/lucy,apache/lucy,nwellnhof/lucy,rbevers/lucy,nwellnhof/lucy,rectang/lucy,pombredanne/apache-lucy,apache/lucy,pombredanne/apache-lucy,rbevers/lucy,rbevers/lucy,rectang/lucy,apache/lucy,rbevers/lucy,apache/lucy,rectang/lucy,rectang/lucy,kidaa/lucy,pombredanne/apache-lucy,kidaa/lucy,kidaa/lucy,pombredanne/apache-lucy,rectang/lucy,nwellnhof/lucy,nwellnhof/lucy,apache/lucy,nwellnhof/lucy,rbevers/lucy,rectang/lucy,pombredanne/apache-lucy,pombredanne/apache-lucy