Added basic site specific files

Added the following files using template from Travel site and updated accordingly:
  * Rakefile
  * _config.yml
  * CNAME
  * foot-scripts.html

Ran `npm install` & `bundle` to update the dependencies for the site
Changed foot.html to remove the sidebar
Added album.html layout file & albums.html partial template file
To make this site work the way I want changed the index.html file to list the gallery
categories (stored in _data/categories.yml), then created pages for each category from
the existing site that list posts/galleries by year
Added some of the galleries so there is something to test
Made the 'Other' category page loop through subcategories then created subcategory
pages for the subcategories available at the moment
Made the 'Travel' category page loop through trip details (stored in _data/trips.yml),
then created subcategory pages for each trip that has been added so far
Uploaded header.jpg image file for the head of the page
Updated flickr.rb plugin to allow just a thumbnail image (without a link) to be
displayed on album lists
Updated archives.html to better suit the site. Now displays thumbnails for each post
Updated main.css, foot.html & head.html to work with the modified layouts