new appendable file need to have its first memory mapping occur on a page boundry.  Added supporting code.
new appendable file need to have its first memory mapping occur on a page boundry.  Added supporting code.

IMCG/levelDB,icholy/leveldb,icholy/leveldb,IMCG/levelDB,tempbottle/leveldb-1,basho/leveldb,icholy/leveldb,basho/leveldb,IMCG/levelDB,tempbottle/leveldb-1,tempbottle/leveldb-1,basho/leveldb