Make PolyCompiler abstract.
Make PolyCompiler abstract.

PolyQuery is abstract; PolyCompiler should be, too.  Also, remove
declaration of `new`, which does not have an accompanying
implementation.

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