Fix Issue 10297 - Memory safe D spec is out of date

Link to spec from front page instead of safed.html article.
Replace 'Proscribed Forms' section with link to @safe function
attribute.
Introduce @safe, @trusted.
Add note about array bounds checks.
Remove unimplemented -safe switch
List a few examples of unsafe operations
Issue 12273 - Added documentation for -color[=on|off] flag
Merge pull request #605 from lionello/color

Added documentation for -color
Fix misspelling of publicly.
Merge pull request #607 from jmdavis/publicly

Fix misspelling of publicly.
http for links to gdcproject.org missing
Merge pull request #608 from schuellerf/patch-1

http for links to gdcproject.org missing
Update beta announcement and correct video links

Links to video for DConf 2014 incorrect. Update announcement to reflect availability of v2.066.0-b1.
Insert link to beta announcement.
Merge pull request #600 from ntrel/update-safe-spec

Fix Issue 10297 - Memory safe D spec is out of date