Allow accessing a prefix of the database file using mmap and the remainder using read and write.
When recycling an lsm cursor, reset the flags field.
Fix a compressed database mode bug.
Fix some test cases to account for sqlite4 memory mapping the file.
Merge prefix-mmap branch with trunk. This allows lsm to memory map a prefix of the database file and use regular read and write system calls to access the remainder.
Fix various issues in lsm_file.c.
Fix further small issues in lsm_file.c.
Fix a bug in database initialization.
Add tests to sqltest.