Rename Application and Execution Context classes

The current pre-packaged execution context and application classes are not really named in a way that makes their functionality clear.

The following is a proposed rename of the pre-packaged classes:

Current Class	New Class	Alternative Class
`SimpleContext`	`TemplateCtx`	`Context_stored_nowhere(?)` or `Context_no_store(?)'
`SimpleAppContext`	`ClientSessCtx`	`Context_stored_client`
`SessionAppContext`	`ServerSessCtx`	`Context_stored_server_process`
`SessionFileAppContext`	`FileSessCtx`	`Context_stored_server_file`
`SimpleApp`	`ClientSessPageObjApp`
`SimpleSessionApp`	`ServerSessPageObjApp`
`SimpleSessionFileApp`	`FileSessPageObjApp`
`ModularApp`	`ClientSessPageModApp`
`ModularSessionApp`	`ServerSessPageModApp`
`ModularSessionFileApp`	`FileSessPageModApp`
`RandomModularApp`	`ClientSessPageModByURLApp`
`RandomModularSessionApp`	`ServerSessPageModByURLApp`
`RandomModularSessionFileApp`	`FileSessPageModByURLApp`

The New Class identifies where the session is stored (ClientSess, ServerSess, or FileSess), specifies the page mechanism (PageObj, or PageMod), and optionally specifies that the page is selected ByURL. Execution context classes have a Ctx suffix and application classes have the App suffix. The TemplateCtx class is a special case, it is used for template only functionality (no session, no pages, no application).

In any event, if the KeywordArguments proposal went ahead we would not need any of these classes.

The problem with the Alternative Class is twofold; the scheme does not extend to the entire set of classes, and the naming convention does not follow the Python style.