[Setools] Gjallar

[Keith Hodges]

Some more informal Gjallar documentation:

Keith

======================================================================
In moving to Seaside 2.8

Deprecated api.
- html heading: 'text' level: 3. is now html heading level3; with: 'text'.
- html image fileName: is no more.
====================================================================== 
Revised access to ini file settings.

Rationale:
Tidy the global settings api a little.
Application installation chooses from available ini files.
Gjallar can be distributed with a number pre-defined out of the box 
configuration files for different roles/installation types. (e.g. db 
server,  web server,  personal installation etc)

usage:
Access to settings from the typical Gjallar domains:
- everywhere: Q2Session current settings
- in the model: Q2Object settings
- in the ui: a Q2ChildComponent settings

#settings obtains an interface onto the iniFile named in the 
'/seaside/config' configuration preference #settingsFile named in the 
seaside #gjallar group defined by Q2GjallarConfiguration.

- 'Q2GjallarSettings clear' is included in 'Q2Gjallar cleanImage' to 
clear ini files cached in memory.

When an iniFile is read, it notes its own expireTime as specified by 
#inifileSeconds
on future accesses if the the file has expired it will be re-read. If 
#inifileSeconds is 0, it will be read once only.

As a convenience settings may be referred to directly with message 
sends, e.g.
self settings databaseDirectory.

References to #gjallar have been replaced with the equivalent of 'self 
settings systemName'.

The exisiting Q2Object interface to settings is still present 
(effectively deprecated) but has been re-routed via #settings. There are 
55 senders of the old Q2Object api to migrate.