Update for v5.11.0

[chorrell]

Also formatting tweaks to make 0.10 and 0.12 consistent with the other
images

Test build looks good!

https://travis-ci.org/chorrell/docker-node/builds/124888504

[chorrell]

Missed the update to generate-stackbrew-library.sh:

This:

array_0_12='0';
array_4_4='4 argon';
array_5_10='5';
array_6_0='6 latest';

Should be this:

array_0_12='0';
array_4_4='4 argon';
array_5_11='5';
array_6_0='6 latest';