update validation for runtime subsitutions

- use VALIDATION instead of metadatas
- Validation blocks are mandatory, not recommended
update doc site with beta3 release
include announcements on index page
add reference to ogrtindex and gdaltindex utilities
Fixed a typo
Merge pull request #9 from homme/branch-6-0

Fixed a typo
add doc for wfs_geometryname parameter
Fixed a few typos in the WCS document
update RFC82
fix formatting
Modified the layer dump parameter description (mapserver/mapserver#3830 )
Modified the layer dump parameter description (mapserver/mapserver#3830 )
Modified the mapscript layer dump parameter description (mapserver/mapserver#3830 )
Modified the mapscript layer dump parameter description (mapserver/mapserver#3830 )
update MSSQL data input document for direct OGR connections, and add examples
update MSSQL data input document for direct OGR connections, and add examples
minor
Adding links to the documentation for earlier versions
Added the current version to the documentation page for earlier versions
Changed Mapserver to MapServer on the documentation page for earlier versions