Merge pull request #346 from aorinevo/patch-2

Update README.md
added maketext call for string "Homework Sets"
added maketext call for the string "There is no additional grade information. The spreadsheet file $filePath cannot be found."
added maketext calls for strings 'Chapter:', 'Section:' and 'or Problems from'
Merge branch 'maketext' of github.com:heiderich/webwork2