I can add or update comments about the file I added

- Have a comment/description field in FRS when I add a file
- Update addFile and getFileInfo() SOAP methods
- Add a new method updateFileDescription () to update "Comments/Description" field

Examples:
/**
* addFile - add a file in the file release manager, in the release $release_id, in package $package_id of the project $group_id with given values
*
* @param string $sessionKey the session hash associated with the session opened by the person who calls the service
* @param int $group_id the ID of the group we want to add the file
* @param int $package_id the ID of the package we want to add the file
* @param int $release_id the ID of the release we want to add the file
* @param string $filename the name of the file we want to add (only file name, not directory)
* @param string $base64_contents the content of the file, encoded in base64
* @param int $type_id the ID of the type of the file
* @param int $processor_id the ID of the processor of the file
* @param string reference_md5 the md5sum of the file calculated in client side
* @param string $description the description of the file
* @return int the ID of the new created file,
* or a soap fault if :
* - group_id does not match with a valid project,
* - package_id does not match with a valid package,
* - package_id does not belong to the project group_id,
* - release_id does not match with a valid release,
* - release_id does not belong to the project group_id,
* - the user does not have the permissions to create a file
* - the file creation failed.
*/
function addFile($sessionKey,$group_id,$package_id,$release_id,$filename,$base64_contents,$type_id,$processor_id,$reference_md5, $description)


/**
* getFileInfo - returns an FRSFile metadata corresponding to the file identified by file_id that belongs to the release
* release_id, in the package package_id, in project group_id,
*
* @param string $sessionKey the session hash associated with the session opened by the person who calls the service
* @param int $group_id the ID of the group the file belongs to
* @param int $package_id the ID of the package the file belongs to
* @param int $release_id the ID of the release the file belongs to
* @param int $file_id the ID of the file we want to retrieve the metadata
*
* @return array FRSFile that belongs to the project identified by $group_id, in the package $package_id, in the release $release_id, with the ID $file_id
* or a soap fault if group_id does not match with a valid project or if package_id does not match with group_id, or if release_id does not match with package_id, or if file_id does not match with release_id.
*/
function getFileInfo($sessionKey, $group_id, $package_id, $release_id, $file_id, $description)

/**
* updateFileDescription – update the description of a file in the file release manager, in the release $release_id, in the package $package_id of the project $group_id with given values
*
* @param string $sessionKey the session hash associated with the session opened by the person who calls the service
* @param int $group_id the ID of the group we want to add the file
* @param int $package_id the ID of the package we want to add the file
* @param int $release_id the ID of the release we want to add the file
* @param int $file_id the ID of the file we want to retrieve the metadata
* @param string $description the description of the file
*
* @return boolean true if the description has been updated, false otherwise
*/
function updateFileDescription($sessionKey,$group_id,$package_id,$release_id, $file_id, $descirption)