Bugfix in dyn_saveas

Fixed a bug for the non-Octave version where only the last active figure
was printed instead of the figure with the actual handle. Octave
eps-version still needs to be taken care of.
(cherry picked from commit cd26c3cebd82140c8354cd6596d19d9459171fad)
Fix dyn_saveas for Octave
(cherry picked from commit c58aebd2ef1af574ad14e6186375b8c729ed0e7f)
Bugfix in rplot

Make other plot types take into account that variables are in rows, not
columns
(cherry picked from commit e76828bb9cca0b4888b9f2d0ad3af568e4eeda92)
Add warning for variance decomposition at order=2

At order=2, the variance decomposition is still based on order=1. This
commit introduces a warning. See issue #278
(https://github.com/DynareTeam/dynare/issues/278). This information that
the variance decomposition is only triggered at periods=0 has been added
to the manual.
(cherry picked from commit 98ec0095dfe22acf3896c3dac74c4a71219fc019)
Bugfix in rplot + typo correction
(cherry picked from commit 1df8bf15c2ea3fbe145f5dc8dfe6625be51e0a72)