Update forusers_index.html

should fix link to documentation, issue #84
added gaia logo to sponsors image
fix to center logos
Merge pull request #105 from anitagraser/master

added gaia logo to the sponsors image for the front page
Merge pull request #103 from anitagraser/patch-6

Update forusers_index.html
rewriting and fixing download pages
adding catalan as language
fixing some build errors
minimal script fix
make latest 2.0 instead of 2.0.0 ...
fixed key and ubuntu and debian downloads #104
Donors added
little i18n fixes, added zh_TW as language
fix typo and point to both osgeo4w 32bit and 64bit installer
adding timestamp for checking build times
moving disclaimer a little
fixing make all
adding (forgotten) english build to 'make all' ...
add Testing/QA manager to PSC page
PSC: remove BTS responsibility from RM (now overseen by Testing/QA)