Remove unused argument mapTestPool for ConnectInputsGameTx.
Remove unused argument nHeight from AddTxIndex.
Implement real testpool for ConnectInputs in mining mode.

Don't use txindex (and its "spent" information) at all in ConnectInputs,
instead use a memory testpool designed for that purpose.  This will
allow to remove the "spent" data completely from CTxIndex.
Remove isSpent completely from CTxIndex.

Get rid of the spent information in CTxIndex, since it is no longer used
(rewrite the UTXO rescanning on the way to not depend on it).  Now,
CTxIndex *only* contains the disk position.
Merge pull request #80 from domob1812/remove-spenttype

Tweak blkindex.dat further.