redone Hadoop V1_V2 chapter
polishing index.xml for publication
Merge branch 'master' into dev
Merge branch 'dev'
image refactoring
tweaking book css
Merge branch 'master' of github.com:markkerzner/HadoopIlluminated
Merge branch 'dev' of github.com:markkerzner/HadoopIlluminated into dev
Merge branch 'master' into dev