Disable Travis CI.

- Remove .travis.yml, common/travis/docker.sh.
- Change references to travis to be more generic.
- Manual.md: Orient against using CI logs in broken= or nocross=.

common/travis/docker.sh

@@ -1,18 +0,0 @@
-#!/bin/sh
-#
-# docker.sh
-
-[ "$XLINT" ] && exit 0
-
-DOCKER_NAME=${DOCKER_NAME:-void}
-
-/bin/echo -e "\x1b[32mPulling docker image $DOCKER_BASE-$BOOTSTRAP:$TAG...\x1b[0m"
-docker pull $DOCKER_BASE-$BOOTSTRAP:$TAG
-docker run -d \
-	   --name $DOCKER_NAME \
-	   -v "$(pwd)":/hostrepo \
-	   -v /tmp:/tmp \
-	   -e XLINT="$XLINT" \
-	   -e PATH="$PATH" \
-	   $DOCKER_BASE-$BOOTSTRAP:$TAG \
-	   /bin/sh -c 'sleep inf'