Updated tutorial about categoryblog.
Some minor updates to hakyll site.

- Hide image captions.
- Remove old tutorials.
- Some minor changes to the tutorials.
Added update note on tutorials page.
Version bump.
Updated zip files.
Fixed zip file url's.
Updated changelog.
Dug in git commits to restore changelogs.
Type fix by minh thu.
Added test case for non-metadata pages.
Moved Arbitrary Template instance to tests.

This way, the code for Text.Hakyll.Internal.Template is
cleaner, and our library does not depend on QuickCheck
anymore.
Added some links to examples on hakyll homepage.
Added fix to allow dashes in pages.

Hakyll splits pages into metadata sections by lines starting
with `---`. Because of this, thing like

    Header
    ------

    Some text.

will not parse. This commit fixes this, by fixating the length
of the the dash pattern -- all dashed lines should contain the
same number of dashes. Therefor, you can use something like

    ---
    title: Foobar
    ---

    Header
    ------

    Some text.
Fixedencoding error in RSS feed.
Add tutorial section about syntax highlighting.
Expose pandoc options (patch by JD Marble).
Update changelog for 2.1.
Add possibility to change URL through Arrows.
Typo fix by masak.
Server allows URL's containing '?'.