fixed formatting re bullets preceded by html <a> tag
update sidebar to remove 'Contents' which looked like it applied to one section only, whereas it's all contents
updated version of realtime segment propagation
update process flow diagram to be correct
added definition for ephemeral node, a ZK concept that occurs in the docs
updated definition of ephemeral node
fixed typo
added titles since there is no other indication other than URL as to which page has been selected from the left-side nav menu
Merge branch 'master' into igalDruid
Merge pull request #314 from metamx/igalDruid

Updates to Documentation to improve concepts and update small bugs in the segment flow