Remove paredit stuff from prelude-common-lisp.el

The paredit backspace override without having paredit-backward-delete-key defined by paredit was breaking slime loading. I commented this out rather than deleting it since I noticed you had just commented out other paredit stuff elsewhere
Merge pull request #351 from capdevc/patch-1

Remove paredit stuff from prelude-common-lisp.el
Remove melpa package from list of default packages
Minor cleanup
When copying the current line discard its newline (fixes #347)
Use helm-projectile directly (fixes #352)
Set sp-cancel-autoskip-on-backward-movement to nil
Add grizzl to the default list of packages
Add flx to list of default packages
Correct substatement indentation in c-mode (fixes #342)
Add prelude-duplicate-and-comment-current-line-or-region (fixes #348)
Fix ido-ubiquitous deprecation warning
Remember the last 500 visited files