Stdout enhancements

Two minor ui enhancements.

1) If the last character in NINJA_STATUS is a '\n', then print a '\n'
instead of a '\r' at the end of the edge description.

I would like the ability to turn off the '\r' feature that prints the
edge description on top of the previous one. Setting TERM='dumb' will do
this but it also strips the color from clang error messages. This change
adds this feature without adding a new command line flag.

2) When a command fails, reprint the edge description before printing
the full command.

When a build fails, its nice to make a change and then only rebuild the
target that failed. This change makes is easy to see the target that
failed.