added note about accessing firefox options dialogue on Windows
Merge pull request #7 from djmattyg007/patch-1

added note about accessing firefox options dialogue on Windows
Initial Chapter 9: Using VPN
Missing .md extension
Added VPN on Ubuntu
Added VPN on OS X
Finished Chapter 9: Using VPN
Added Chapter 10: Disk Encryption
Added Chapter 11: Call Encryption
Added Chrome extensions
Added Chapter 12: Instant Messaging Encryption
fixed broken chrome:// uri
Added Chapter 13: Secure File Sharing
Added final Chapter 14: Appendices
Updated README
README update about peer-review process
Merge pull request #8 from therealplato/master

Added Google Chrome extensions and settings
Updated peer review and publishing in README
Clearly mention book license CC-BY-SA 3.0
Edited 'keeping passwords safe' for brevity and clarity