Expansion of section 3.1 into multiple parts

3.1 System Requirements
3.1.1 Supported Platforms
3.1.2 Firewall Configuration

New section describing firewall requirements for various Foreman elements.
Adding nice table for 1.3 installer options
Remove stray full stops
Add port 3000 back for WEBrick service
Add missing URL parameter
1.3 contributors
Merge pull request #107 from domcleal/contributors

1.3 contributors
Add script to work out contributors list
Update compute resource info for 1.3
Merge pull request #108 from domcleal/1.3-cr-update

Update compute resource info for 1.3
Fix backup section link
Add link to upgrade notes from upgrade instructions
Typo fix
Merge pull request #110 from ekohl/patch-1

Typo fix
fixes issue #109 add scroll to the table of content.
Merge pull request #112 from abenari/gh-pages

fixes issue #109 add scroll to the table of content.
Fix precompile typo
beginning developer documentation for the v2 api standards
Remove missing content text
Add CentOS Dojo talk