weavetools -> weaveexec

This is to make a visible break with previous releases, such that a
newly downloaded weave script will definitely work.

Without this change in name, an existing weavetools image that doesn't
include the script might be invoked, resulting in a confusing message
for the user.

weaveexec/Dockerfile

@@ -0,0 +1,7 @@
+FROM gliderlabs/alpine
+MAINTAINER Weaveworks Inc <help@weave.works>
+WORKDIR /home/weave
+RUN ["apk", "add", "--update", "ethtool", "conntrack-tools", "curl", "iptables", "iproute2", "docker"]
+RUN ["sh", "-c", "rm -rf /var/cache/apk/*"]
+ADD ./weave /home/weave/
+ENTRYPOINT ["/home/weave/weave"]