The incomplete Guide to Lumiera Configuration

This shall become a reference of all (most) lumiera configuation keys.
So far this is only prelimary located in the doc/devel dir and will be
moved to the documentation wiki as soon as it becomes available.

doc/devel/config_guide.txt

@@ -0,0 +1,80 @@
+The incomplete Guide to Lumiera Configuration
+==============================================
+
+DONT EDIT THE CONFIG IF YOU DONT KNOW WHAT YOU ARE DOING!
+Misconfiguration will break Lumiera and may destroy all your data!
+
+Order is roughly alphabetically, depending on the mood of the writer.
+Defaults are noted if present. Not all are implemented yet.
+
+General Introduction
+--------------------
+
+Lumiera uses plaintext files with a INI file like syntax for
+configuration. This Syntax is strictly line based. There are only a
+few syntactic elements.
+
+TODO:describe config syntax here
+
+Config Subsystem
+----------------
+
+The path where Lumiera searches its configuration. Single components are
+separated by colons as in PATH and other such environment variables.
+Here it might be handy that any Lumiera configuration can be
+overridden by a environment variable:
+'LUMIERA_CONFIG_PATH=somewhere:else lumiera ...'
+A default are initialized at installation time, this is important to
+bootstrap the whole configuration system.
+
+ config.path
+
+
+The config system check for a preferred format when writing config
+entries. For each key 'foo.bar', these can be overridden with a key
+'config.format.foo.bar' linking to the desired format.
+
+ config.formatkey ='config.format.%s'
+
+
+The following are links to the default formatting when no explicit
+format is set for a key. Changing these to a wrong type will break the
+system!
+
+ config.formatdef.link < config.formatstr.link
+ config.formatdef.number < config.formatstr.number.dec
+ config.formatdef.real < config.formatstr.real
+ config.formatdef.string < config.formatstr.string
+ config.formatdef.word < config.formatstr.word
+ config.formatdef.bool < config.formatstr.bool
+
+
+This are the low level formating specifications for the buildin
+types, DONT TOUCH THESE!
+
+ config.formatstr.link = '< %s'
+ config.formatstr.number.dec = '= %lld'
+ config.formatstr.number.hex = '= 0x%llX'
+ config.formatstr.number.oct = '= 0%llo'
+ config.formatstr.real = '= %Lg'
+ config.formatstr.real.dec = '= %Lf'
+ config.formatstr.real.sci = '= %Le'
+ config.formatstr.string = '= %s'
+ config.formatstr.string.dquoted = '= \"%s\"'
+ config.formatstr.string.quoted = '= ''%s'''
+ config.formatstr.word = '= %s'
+ config.formatstr.bool = '= %d'
+
+
+Plugin System
+-------------
+
+The path where Lumiera searches its plugins. Single components are
+separated by colons as in PATH and other such environment variables.
+Here it might be handy that any Lumiera configuration can be
+overridden by a environment variable:
+'LUMIERA_PLUGIN_PATH=somewhere:else lumiera ...'
+Sensible defaults are initialized at installation time.
+
+ plugin.path
+