Merge pull request #27 from timrichardson/master

Documentation about mail.settings.tls
fixed st_x and json field type
May spell fixes, thanks Denes
added SUPPORT and CONTRIBUTE paragraph on chapter 1
typos and PythonAnywhere polishings
added db_codec parameter description
Various ...
Some clarifications
Update sources/29-web2py-english/09.markmin

Replaced the abandoned facebook module by a forked project. The original link is broken
typos
Merge pull request #28 from nicozanf/master

Added Support and Contribute paragraphs, PythonAnywhere polishings and small typos
Merge pull request #29 from spametki/master

An alternative download link for Facebook's GraphAPI
edited acknowledgements
jsonrpc2
fixed 100->100.0, thanks Niphlod
fixed pgp, thanks Martin
Fix negation parenthesis and add precdence explanation.