concurrent access corrections on NGet, Range, NRange, GreaterThan, Gr…

…eaterThanEqual, LessThan, LessThanEqual

minor comments on lsmt structure

write ahead log corrections and recovery corrections

sstable sequential search corrections. Also corrections on more granu…

…lar sstable searching

pager implementation

avl path correction

correct mod file to be a package on github

updated read me

close method on read me

test corrections