Christmas presents

Jérôme Pansanel has completed the new serialization code for mychem and pgchem, so there is no need to handle stereo and non-stereo queries differently anymore. I have moved the index functions to GCC's vector extensions where applicable, and the first result is that index build times have been roughly cut by half while substructure search times have improved, but not that much.

Index build times

System	Index build time
pgchem with OpenBabel or Indigo	352137 ms
pgchem with OpenBabel or Indigo vectorized	192815 ms

OpenBabel with binary storage and FP2 fingerprint vectorized

Query	Hits	no Index	Hits	with Index
GH2	4840	98416 ms	4840	17044 ms
GH7	260	94053 ms	260	1564 ms
GH13	580	113690 ms	580	34504 ms
GH16	26910	99365 ms	26910	55154 ms

Merry Christmas and a happy new year!