updated ingame help screenshots and description of orbs
updates of ingame manual, part 1

* removed undergound illuminated image since it is not described in the
text
* updated description for orbs
* updated screenshots for orbs
updated screenshots for manual, part2

* created new screenshots
* wired in screenshots in manual.txt
* updated README to reflect latest version
removed old screenshots from manual
Merge branch 'master' of github.com:wesnoth/wesnoth-old