Merge pull request #5 from asQuirreL/dev

Lesson 3: Ashok's sections.
Added dict & functions for lesson 3
Word-wrapping fixed
Indentation fixed for code
Lesson 3: (James' sections) Fixing typos and trailing whitespace.
Lesson 3: (James' sections) Spacing out paragraphs, slight rewording

Changing references to "arrays" to "lists" as that is what people are
familiar with in this course.
Lesson 3: (James' section) Further example and more spacing out.

Added examples to show how to use `not in` as well as `in`. And
illustrated the multiple values, same key and same key, multiple values
properties more clearly.
Lesson 3: (James' sections) Adding subtitles for dictionary topics

 * Added examples for the `del` keyword.
 * Made a distinction between assignment for the first time, and
   modifying a key
Lesson 3: (James' sections) Added explanation of code reuse.

Also added print statement comments in `absolute` function listing.
Merge pull request #6 from asQuirreL/dev

Editorial Changes
Merge pull request #8 from asQuirreL/james_dev

James' stuff + Editorial stuff.
Lesson 3: (James' sections) Final large set of changes.
Merge pull request #9 from asQuirreL/james_dev

James dev
Added some extra ending tasks
Merge branch 'dev' of github.com:oxcompsoc/www-content into dev
Lists not arrays
Added membership form
Actually added pdf
Started Lesson 4, added anchor tags to parts of lessons so far, and updated
resource index page.
Added tasks 5-8 for lesson 4, and cleaned up task list