partially merged with nithin, with invoked_directory global variable.
removed errors and bugs. Changed path problem from physical layer.
Merge branch 'nithin' into dheeraj

Conflicts:
	include/defs.h
	include/error.h
	include/globals.h
	physical/createcats.c
	physical/error.c
	physical/helpers.c
	schema/closedb.c
	schema/create.c
	schema/createdb.c
select, delete, quit implemented.
join is partially done
Fixed minor bugs that was commented on the github.
Implemented project

- Changed the way ints and floats are converted to byte array
- Fixed several minor stuff
All files are compiled except project, load, print (not present in this branch).
->Completed Join()
->Delete implemented
->Metadata security enabled in destroy and delete
->Fixed malloc problem in create.c:124
->Added some headerfiles in other headerfiles
->Changes of helpers.c, of byte array conversions are NOT present.(obsolete version)
Implemented load
Merge branch 'dheeraj' into nithin

Conflicts:
	algebra/join.c