Add realtime charts

cgi: fix  change  links  of chunkserver
Refactor code

fix typos

Refactor code part 2
master, chunkserver: Fix adding data of chart

remove spaces
common: Fix generating realtime charts
csv: Add  column titles
common: Remove unused code
common: Remove support for older chart formats
cgi: Add realtime charts auto refresh
Fix variable names

remove magic number
common, cgi: Remove  magic number
common: Fix bug no data on realtime charts

common: change prefix of names: APPROXIMATION_COUNTER to ELEMENTS2AVG
Fix scale in realtime charts