fix typos
Merge pull request #1 from gaodayue/fix_typos_in_day1

fix typos in day1
problems found in students' emails
more problems
add feedback & one problem
add README.md to organize the content
some minor changes
add README.md to organize the content
meeting/agenda/minutes
grammer
name in email account setting
reading
agenda & minutes
correct minor errors
add README to day3
add README to day4
add README to day5
add README to day6
add README to day7
add README to day8