[ENH] Improve usability and user-friendliness of last page

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@50456 b456876b-0849-0410-b77d-98878d47e9d5
[SEC] installer: Convert $_GET parameters related to multitiki to $_POST. Please test as I don't have a multiki running to test with.

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@50461 b456876b-0849-0410-b77d-98878d47e9d5
[ENH]Usability. As discussed in the March 2014 Webinar, remove the amount of text shown by default in each screen of the Profiles Wizard and add some screenshot to (almost) each profile (debug mode: for the time being I don't know what to add as screenshot). More text is shown when passing the mouse over the help icon. So far, screenshot images are from *.t.o remote sources; shall screenshots be bundled in the tiki file tree?

git-svn-id: file:///var/local/code.tiki.org/tikisvn/branches/12.x@50463 b456876b-0849-0410-b77d-98878d47e9d5