README: Bump example snapshot versions from 2.71 to 3.2

Now that we have releases in the 3.x line, we should be pointing users
in that direction.  These version numbers should probably be bumped
with each release :(.

Signed-off-by: W. Trevor King <wking@tremily.us>
feed: Remove <table> elements from HTML mail

These were not semantically correct ;).  Based on a patch by Rui Carmo
[1].

[1]: https://github.com/rcarmo/rss2email/commit/2a015bce9d701035b9af874bd56c46f92382e668

Based-on-patch-by: Rui Carmo <rui.carmo@gmail.com>
Signed-off-by: W. Trevor King <wking@tremily.us>