Squashed merge of master branch

git-svn-id: https://svn.r-project.org/ESS/trunk@5455 0bbaf3bd-34e0-0310-bf65-c717079852d4
exponential waiting time in ess-wait-for-process

git-svn-id: https://svn.r-project.org/ESS/trunk@5456 0bbaf3bd-34e0-0310-bf65-c717079852d4
new ess-with-current-buffer macro wraping transfering important ESS local vars
between buffers

git-svn-id: https://svn.r-project.org/ESS/trunk@5457 0bbaf3bd-34e0-0310-bf65-c717079852d4
extract the core of  ess-display-temp-buffer into  ess--flush-help-into-current-buffer

git-svn-id: https://svn.r-project.org/ESS/trunk@5458 0bbaf3bd-34e0-0310-bf65-c717079852d4
fix #35 (Autocomplete quick-help causes emacs to hang for functions in multiple packages)

git-svn-id: https://svn.r-project.org/ESS/trunk@5459 0bbaf3bd-34e0-0310-bf65-c717079852d4