* fixed some white-spaces

FZJ Logo with Institute

See merge request kabadshow1/beamertheme-juelich!14

Use CD-correct Canvas Margins

See merge request !13

Implements a PGF Key for page layout; adapts tutorial

See merge request kabadshow1/beamertheme-juelich!11

Fix Date Alignment

Closes #12

See merge request kabadshow1/beamertheme-juelich!10

Just like for footer element{1..3}, footer element4 can now be set via `\setbeamertemplate`. This will replace the FZJ logo in the lower right corner by the user's choosing. Intended usage is a FZJ logo which has the institute name to the right of it.
That also is the main difference of `\setbeamertemplate{footer element4}` to 1..3: The vertical margins are adapted to match the align of the FZJ logo.

A section has been added to the tutorial to show and explain the usage.

This moves over to a non-whitespace'd version of the FZJ logo for this. I also fix most of the occurances of 0.5cm to 0.05\paperheight (which is the same for the 1610 aspectratio, but not for other ratios). The partner logo placements have been moved as well.

This is the last part of the re-implementation of merge request !7

In accordance to what was discussed in #3, this implements a PGF Key to steer the multi page layout, `page layout`. Per default, it is not used. When it is used, the option to the key is directly passed to `\pgfpagesuselayout{OPT}`, for example `\fzjset{page layout=2 on 1}`.

Since the page layout is actually different from handout, I removed the `\mode<handout>` part from the key's definition. Users should rather wrap the `\fzjset` call in the `\mode<handout>` macro.

The tutorial has been changed to reflect (and explain) that; the minimal_handout.tex file changed as well.

This fixes #12, and is an extraction of the stuff tried to merge with !7

Issue 13 (Empty subtitles waste space on title slides)

See merge request kabadshow1/beamertheme-juelich!8