rev: simplify new line detection and impossible test

The new line detection is earlier using only '\n' so there should not be
need to search for '\r' later.

The detection whether allocated address is pointing to null seems to be
unnecessary.  Assuming xmalloc() returned valid address space the address
should never be 0.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
rev: reduce stream checking when closing read-only file descriptor

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
dmesg: add iso-8601 time format

The ISO-8601 should be welcomed by anyone who tries to parse dmesg time
stamp, and compare them across servers.  Time format tries to imitate
coreutils 'date --iso-8601=ns' output, but instead of having nanoseconds
the dmesg is using microseconds.

Reference: http://www.cs.tut.fi/~jkorpela/iso8601.html
Addresses: http://xkcd.com/1179/
Signed-off-by: Sami Kerola <kerolasa@iki.fi>