Regenerate the Bootstrap stylesheet.

This is mostly to fix the .btn-primary rendering. I have also incorporated
the hover colour into the Bootstrap stylesheet, so this is removed from
the Site.css stylesheet.

I will document the full set of overrides in #37 so we can refer back to
it if we need to do this again.
Fix text shadow on navbar text.

Change the text shadow from green to a mid gray (#666666). This is
subtle enough to not be obvious, but makes the text much more defined
and easy to read.
Added icons for iDevices.
Added image files to project.
Change the text of the email link
Merge pull request #59 from SimonPStevens/idevice-icons

Fix #27: add iDevice icons.
Merge pull request #61 from adrianbanks/change-email-link

Change the text of the email link.
Add Software East logo to project.

Add image file, and include it in the web project.
Add Software East logo to Sponsors page.
Add Software East logo to side bar.
Merge pull request #66 from alastairs/software-east

Add Software East as a sponsor
Merge pull request #45 from alastairs/fix-bootstrap

Fix #37: Regenerate the Bootstrap stylesheet.
Remove some of the jaggies from the logo.

Thanks @adrianbanks for fixing this.
Merge pull request #67 from alastairs/better-software-east-logo

Better Software East logo
re-order the sponsors
add a new speakers page to show the details of a speaker
Merge pull request #68 from adrianbanks/issues/23

Fix #23: Sort sponsor logos by sponsor level
style the current speaker the same as the current user's sessions
swap some complex code for something simpler
render sessions and speakers more consistently