add pollster ratings
add raw poll data
add pollster ratings readme
remove csv files
add tsv files
fix readme
full pollster stats spreadsheets
update readme
Revert "add tsv files"

This reverts commit dc1ba0054b4045807b3db3b25c6185af52b94c08.
update excel file column names
add raw data tsv files
update spreadsheet
update README
Merge branch 'master' of https://github.com/fivethirtyeight/data
update definitions
add pollster ratings to readme
tweak readme text