added test of readline/readlines - issue #1763
added test of readline/readlines - issue #1763

with opened files, readline() seems to be working ok
but  readlines() is having some problem with linux
text files; binary mode works fine.

When readlines() is used,
files ending by '\n\n' are not having correct number of lines.

brython-dev/brython,brython-dev/brython,brython-dev/brython