Lower PHP requirement, remove ext-mssql conflict
Lower PHP requirement, remove ext-mssql conflict

* The library should work on much older versions of PHP
* The library doesn't conflict with the mssql extension because the entire
  file is wrapped in the following if statement:

      if(!function_exists('mssql_connect')) {

* This will allow people running on PHP5 to include this compatibility
  library prior to upgrading their systems to PHP7, otherwise Composer
  complains with the following:

      Package hexblot/mssql-compat at version  has a PHP requirement incompatible with your PHP version

hexblot/mssql-compat