README: Clarify that it doesn’t matter where the repository is cloned, and document ~/.extra
README: Tweak the part about ~/.extra
.bash_prompt: Add screenshot URL
.bash_profile: Be sure to source `.bash_prompt` first, in case it sets the PATH and subsequent dotfiles rely on it
.aliases: Use `sudo` to empty local trash as well
nerfing .vimrc's setrelativenumber and undodir options in case of older vim version
delet some uneeded stuff