Fixed calls of the form (- (or arg 1)) in some backward commands
Fixed prefix arguments
Improved `sp-down-sexp`. Calling it with C-u prefix will now make it descend "infinitely" deep, meaning as deep as possible.
Fixed `' pair recognition in strings in modes where `' are "expression prefix characters" (so basically only LISPs)
Added `sp-get-list-items`. Function can be used to query about the contents of a list.