Fix return values of qes_seq_fill* funcs

These functions returned 1 for success, 0 for failure. Throughout the
library, we try and make the opposite true. So, i've reversed the
meaning of the return values for these functions.

Changes to be committed:
	modified:   src/qes_seq.c
Add test of seq_copy & fix return val of seq_fill

Add a test of qes_seq_copy, and fix up the tests to accept the new
return values of qes_seq_fill and friends.

Changes to be committed:
	modified:   test/test_seq.c
	modified:   test/tests.h
Add test for equality of src & dest in seq_copy

If dest == src, then we don't copy sequences. Update test with a case
that tests this.

Changes to be committed:
	modified:   src/qes_seq.h
	modified:   test/test_seq.c