Write a test for base32_encode_small_block
Actually add the test to the suite
Add padding in case of length 4
Fix bas32_encode_small_block() for length 1

The first encoded character was incorretly set. Fixed.
Fix base32_encode_small_block for len = 2

The third character wasn't set correctly, wrong left shift and mask
values.
Add test of encode small for data length 4

Test is passing.
Add test for data length 4 (failing)
Fix offset loop for data length 5

Was too long, should only have run once.
Fix correct encoded string, one letter wrong.

The test of base32_encode_small_block() with input data length 4 is now
working.