Common
======
 - title [string<locale>]
    Just a title to be presented to end users.
 - reader [class]
    ADEI class handling connection to the source, examples: DBReader
 - database [array]
    Lists actual databases. It is only a hint to the readers, and they are 
    allowed to provide (in user view) completely different names. 
    However, current READERs are considering that specified names are actual 
    database indentificators which are passed to users. 

    As well it is considered what any database which is actualy specified in 
    database array is active database and there are the data is logged in it. 
    However, the READER could additionaly return the suffixed databases (
    the actual database + arbitrary suffix, normaly refering a date) which
    contain the historical data.
 - multibase
    This disables lookup for suffixied database (see 'database' option)    
 - disconnected [boolean]
    This means what data source is not any more available and only information
    stored in the CACHE should be used.
 - timeout [integer] {us}
    Specifies data source connection timeout
 - ping [boolean]
    To support READERS ignoring 'timeout' option, the 'ping' option instructs
    common reader interface to use ping-before-connect approach in order to 
    avoid connection attempts to dead/inaccessible servers.
 - charset [string]
    Character encoding in which database reports problems


Database based (DBReader, ZEUSReader)
==============
 - driver [id]
    Database driver, like: odbc, mysql, ...
 - sqldrv [id]
    Underlying database engine, should be specified if general libraries 
    (like odbc) are used to access database. 
    Examples: mysql, mssql
 - subdrv [id]
    Actual database driver, should be specified if general libraries (like
    odbc) are used to access database.
    Examples: FreeTDS
 - host [string]
 - port [integer]
    Specifies database port. '0' means - use the database default.
 - user [string]
 - password [string]
 
