Fixed typos etc in editing docs

Conflicts:
	docs/user/editing_basics.rst
Doc syntax formatting to match guidelines
Customization => Customisation

Conflicts:
	docs/user/editing_basics.rst
Typo

Conflicts:
	docs/how_to/placeholders.rst
Updated integration doc to reflect 1.6/1.7 support

Updated suggested software versions of 3rd party apps

Conflicts:
	docs/how_to/integrate.rst
Updated links for the tutorials

Conflicts:
	docs/how_to/integrate.rst
	docs/user/editing_basics.rst
ImageOptim doc images

Conflicts:
	docs/images/basic-page-form.png
First pass at 'editing basics' docs

Moved existing content from the 'integration docs'.
More documentation and screen shots to come but this 'works' for now.

Conflicts:
	docs/how_to/integrate.rst
	docs/images/basic-page-form.png
	docs/user/editing_basics.rst
Updated links to Django docs to point to latest

...instead of 1.2. Changed 1.7 references as well for consistency.

Conflicts:
	docs/how_to/integrate.rst
	docs/how_to/placeholders.rst
fix missed merge indicators
Split basic editing tutorial and reference
Further improvements to user tutorial/basic admin
Merge pull request #3608 from evildmp/user-docs

User-facing documentation