win/tty: fix case where uv_read_start incorrectly reports failure

In very rare circumstances a uv_read_start() call on a uv_tty_t handle
in raw mode would return -1 but there was no actual failure. This patch
fixes that.
win/tty: don't touch insert mode or quick edit mode

Hopefully this fixes joyent/node#4809.
win/tty: fix typo in color attributes enumeration