adding 'a Unix-like OS' as a requirement
throwing a bone to Windows users
adding a message of hope to Windows users, those poor souls...
adding a page describing the use of Synthesize, the install script
capitalizing UNIX, and unawkwardizing a phrase.
capitalizing the other UNIX
Merge pull request #837 from gwaldo/win-users

Windows Users and Synthesize
Adding missing period to document.
Fixed typo for reduceSeries
Improved documentation for areaBetween
Improved documentation for cactiStyle

Explained possible options for system (not letting the reader hunt around for
possible values), as well as culled most info for alignment from:
https://github.com/graphite-project/graphite-web/issues/671
Merge pull request #839 from ojilles/master

Documentation updates for areaBetween, cactiStyle and reduceSeries