install: add Express with EJS

EJS templates are stored at `./public/templates`, ideally should be serverd from both back and front end.
static: better favicon management
static: add humans.txt and robots.txt
styles: add Bootstrap with Font-Awesome and Flatty

- drop HTML5Boilerplate
- add Twitter Bootstrap as CSS framework, with LESS
- plug LESS to client-side
- add Font Awesome icons with LESS
- add Flatty theme from Bootswitch
- reorganize directories, `js/` is now `javascript/`

Index file loads
- `normalize.less`, `print.less`
- `variables.less`, with modified data for Twitter Bootstrap and Font Awesome
- `theme.less`, with Bootswatch and Flatty config
- `bootstrap.less`, `font-awesome.less`, slightly modified to load corresponding files only

This setup will make possible to install both Bootstrap and Font Awesome dynamically (e.g. with Bower).