Adds record

Moves block to it's own file. Bufferpool accepts and returns Records.
A record contains a key and value. Records are created from byte array
key and values.
Adds java program to check sortedness of file
adds record equals and tests
Adds bufferheap and 0-based heap sort

Adds bufferheap. Adds heapsort from golang since it's 0 index based.
Old implementation was 1 based. sort.Interface is awesome.
HeapSort of bufferheap is working!
updates file handle permissions to read/write