improved docs for package

Added explanation for amazon bucket. Added configuration section.
Added example for custom content types.
Improved package documentation.

Added migration section.
imporoved package documentation.

Added 'safety' section.
improved package documentation.

Added 'safety' section.
Merge branch 'documentation' of github.com:martinschoel/collective.contentfiles2aws into documentation
added url generation section
remove security section header
improved docs
fixed README format
Merge branch 'documentation'
prepared 1.0 release