support lowercase key symbols as expected by Capybara
support lowercase key symbols as expected by Capybara

dv/poltergeist,afn/poltergeist,teampoltergeist/poltergeist,ducthanh/poltergeist,dv/poltergeist,twalpole/poltergeist,twalpole/poltergeist,ducthanh/poltergeist,geminiyellow/poltergeist,geminiyellow/poltergeist,geminiyellow/poltergeist,ducthanh/poltergeist,twalpole/poltergeist,dv/poltergeist,twalpole/poltergeist,teampoltergeist/poltergeist,afn/poltergeist,afn/poltergeist,ducthanh/poltergeist,teampoltergeist/poltergeist,geminiyellow/poltergeist,dv/poltergeist,teampoltergeist/poltergeist,afn/poltergeist