Added structs for buffer and cache
Added buffer,h and cache.h (missed in previous commit)
Merge branch 'dheeraj' into nithin

Conflicts:
	physical/filewrapper.c
Merge branch 'nithin' into dheeraj

Conflicts:
	physical/filewrapper.c
Implemented flush page and read page

TODO: Move 'int to byte array' and vice-versa in separate function
Deleted buffermanager.c
Merge branch 'nithin' into dheeraj

Conflicts:
	physical/filewrapper.c
implemented openrel, (need updaterec for checking)
opencats is in halfway