Recenter in ess-eval-linewise. Emacs spuriously resents window point. This is the only way to prevent that.

git-svn-id: https://svn.r-project.org/ESS/trunk@5386 0bbaf3bd-34e0-0310-bf65-c717079852d4
ess-describe-object-at-point: shorter head/tail and make R use R-command-list instead of S-list.

git-svn-id: https://svn.r-project.org/ESS/trunk@5387 0bbaf3bd-34e0-0310-bf65-c717079852d4
ess-describe-object-at-point: show buffer first (useful for heavy objects)

git-svn-id: https://svn.r-project.org/ESS/trunk@5388 0bbaf3bd-34e0-0310-bf65-c717079852d4
ess-describe-object-at-point: if region is active, use it instead of the symbol at point

git-svn-id: https://svn.r-project.org/ESS/trunk@5389 0bbaf3bd-34e0-0310-bf65-c717079852d4
new ess-switch-to-end-of-proc-buffer variable that controls whether C-c C-z
 switches to the end of process buffer. The default is t. You can use prefix
 argument to C-c C-z to toggle this variable.

git-svn-id: https://svn.r-project.org/ESS/trunk@5390 0bbaf3bd-34e0-0310-bf65-c717079852d4