Add note about attr_accessible

This won't work without this.
Fix punctuation error
Change instances of "girls" outside of "Rails Girls" to women to be more
consistent with the railsgirls.com homepage copy "Our aim is to give tools
and a community for women to understand technology"
Merge pull request #85 from ialja/master

added Ljubljana videos with link to lectures
Fixed typos and updated broken bootstrap.min.css link
Fixed typos and updated broken bootstrap.min.css link
Merge pull request #86 from negomi/master

Fixed typos and updated broken bootstrap.min.css link
Merge pull request #83 from didlix/master

Fix punctuation error
Merge pull request #82 from steveklabnik/patch-3

Add note about attr_accessible
Fixed div layout code to make the span4 ideas line up properly in groups of 3
Merge pull request #88 from negomi/master

Fixed div layout code to make the span4 ideas line up properly in groups of 3
Fix path to `rails`

In rails 4.0.0 that is current stable version,
the `rails` script is placed under `bin` not `script`.
Fix link to railsinstaller

Current stable version is 2.2.2.
This version is hosted by only github.com.
Merge pull request #90 from tricknotes/fix-link-to-railsinstaller

Fix link to railsinstaller
Merge pull request #89 from tricknotes/fix-path-to-rails

Fix path to `rails`
need to delete index.html to make it work
Fixed error in 'app/assets/stylesheets/scaffolds.css.scss' filepath
Updated OS switcher to try and auto-detect what operating system the visitor is using.

This will only take place if an OS hasn't already been selected (i.e. when the cookie is not present).
Updated standard app tutorial to include some windows specific tips.
Added a line to instruct the student to remove the index.html file, and added instructions for the coach to discuss route orders and static files.