Editor configuration / Add conditional display of views.

Views can be displayed based on the metadata record content or the service information.

Example: Only display view if standard name contains a value:
```
 <view name="medsea" displayIfRecord="contains(gmd:MD_Metadata/gmd:metadataStandardName/gco:CharacterString, 'MedSea')"
```

Example: Only display view if current user is an administrator.
```
<view name="medsea" displayIfServiceInfo="count(session[profile = 'Administrator']) = 1"
```
ServiceInfo allows to access any Jeeves /root/gui elements.
Editor configuration / Add more documentation. More strict XSD.
Cleaning.
Merge remote-tracking branch 'origin/stable-develop' into improvements/editor-config-display-view-according-to-session-and-metadata
Merge pull request #624 from fxprunayre/improvements/editor-config-display-view-according-to-session-and-metadata

Editor configuration / Add capability to display view according to session and metadata