manual.mk: Prepared manual build for a German translation,
added the path to the English version as last default to avoid copies for not jet translated file.
Manual: Reworked icons for config reference, gesture, and tip now in svg format.
Manual: Put new margin icons in xc manual style and deleted the replaced icon files.
Manual: Warning sign in same style as other margin symbols.
manual: first collection of files for complete german manual XCSoar
Manual: Solved merge issues from Claus new German translation.