* Create telemetry_mssql.sql
SQL to create the speedtest_users table on Microsoft SQL server.
This SQL is based on the original templates, and continues to uses nvarchar for all fields as the templates do – even though some of the fields should be int.
* Added support for Microsoft SQL Server
* New sanitycheck.php page plus required updates to telemetry_db.php
Created a sanity check page to verify that the required PHP extensions are installed, and that it is possible to connect to the database.
* Update README.md - MS SQL support
Added mention of Microsoft SQL Server as a supported DB engine.
* Added missing <tr> to sanitycheck.php
