Use semantic linebreaks; typo: extenal -> external

[semantic linebreaks](http://rhodesmill.org/brandon/2012/one-sentence-per-line/) allow both code and text to be more readable and better suited to diffs, browsing in non-wrapped environments, and plain reading.
Merge pull request #1 from waldir/patch-1

Use semantic linebreaks; typo: extenal -> external
Update algorithms to version in extras/
Changes to classdict entries, because strip() does not remove internal whitespace
Merge branch 'master' of git://github.com/timholy/Images.jl into rsr/io