SpaceIndex macro:adding some sorting parameters

Improve SpaceIndex macro:adding some sorting parameters
Cf.: http://jira.xwiki.org/browse/XCOMMONS-602
I add the sort order parameter:
Name: sort
Optional: yes
Allowed values: creationDate, modificationDate and name
Default value: creationDate
Description: creationDate sorting the list by creation date of documents, modificationDate by update date and name sorting alphabeticaly the list

Example:
spaceindex space="Sandbox" sort="name" /
return the list of Sandbox space alphabeticaly ordering
Include "doc." in $sort parameter
JIRA ISSUE XCOMMONS-602:Add sort options SpaceIndex

Add sorting options on SpaceIndex macro
JIRA ISSUE XCOMMONS-602:Add sort options SpaceIndex

A little bit of cleaning end of line.
JIRA ISSUE XCOMMONS-602: add logic on parameter name

Rename name parameter by docName to respect a "logic" (creationDate and modificationDate) and I incremented the version number.
Update SpaceIndex.xml
Merge pull request #280 from Pbast/patch-1

XWIKI-10441: Add sorting options on SpaceIndex macro.

* Merge the Pull Request.