add lz header
added element type dictionary
added findInDictionary function prototype
written function for  lookup in dictionary
Writed lz78_encode function
fixed encode and findInDictionary functions
written lz78 decode function
fixed lz78 encode and decode funtions. working encode and decode
Fixed packing unnecessary byte
added alignment for elements of dictionary
added include guard in lz.h
Fixed detection of read errors. Added release allocated memory to avoid memory leaks.