Allow configuring cleaning white space on save

This condition is checked when saving if the existing
whitespace-cleanup is set instead of when the when prog-mode is is
entered.  This way it can be over-ridden by either dir-locals or
file-local variables.
Minor refactoring
Merge branch 'master' of github.com:bbatsov/prelude

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Ignore projectile-bookmarks.eld
Fix docstring
Add prelude-clean-whitespace-on-save to README.md

Also fix incorrect indentation in prelude-editor.el changes.
Good catch bbotsov!
Merge pull request #285 from nathanstitt/clean-whitespace-on-save

Make cleaning white space on save an option
Add prelude-indent-defun
Merge branch 'master' of github.com:bbatsov/prelude

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Code style
Code style
Fix a typo
Merge branch 'master' into personal_config