GH_1 - Create default layout that can be reused

Introduced default.html file in _layouts folder. This contains the standard HTML headers etc, and the footer part of the page.

Content is then injected via Jekyll using {{content}}.

index.html was rewritten to make use of this

Signed-off-by: Ippoippo <ippoippo_software@ippoippo.net>
Merge branch 'refs/heads/gh_issue1_create_default_html'