[refactor] Use Elisp style, -p predicates

As discussed in #311 `-p` style predicates
are more consistent with the rest of clojure-emacs projects and the
language in general.

cljr predicates renamed

- cljr--use-multiple-cursors?
- cljr--comment-line?
- cljr--whitespace?
- cljr--inside-prefixed-libspec-vector?
- cljr--even?
- cljr--op-supported?
- cljr--cljs-file?
- cljr--cljc-file?
- cljr--clj-file?
- cljr--dash-in-file-name?
- cljr--already-declared?
- cljr--existing-group-of-defs?
- cljr--point-in-reader-conditional?
- cljr--point-in-reader-conditional-branch?
- cljr--clj-context?
- cljr--in-namespace-declaration?
- cljr--excluded-from-project-clean?
- cljr--empty-buffer?
- cljr--end-of-buffer?
- cljr--qualified-symbol?
- cljr--is-keyword?
- cljr--symbol?
- cljr--keyword-lookup?
- cljr--defn?
- cljr--call-site?
- cljr--no-changes-to-parameter-order?
- cljr--apply-call-site?
- cljr--partial-call-site?
- cljr--ignorable-occurrence?

predicates renamed from dependencies

- -contains? (dash)
- -every? (dash)
- s-contains? (s)
- s-starts-with? (s)
- s-ends-with? (s)
- s-equals (s)
- s-matches? (s)

predicates not renamed as there is no suitable alias

- s-blank? (s)
- s-present? (s)
- s-uppercase? (s)

Author: benedekfazekas