add ess-process-live-p

git-svn-id: https://svn.r-project.org/ESS/trunk@5501 0bbaf3bd-34e0-0310-bf65-c717079852d4
electric debug keys are on C-c M- in ess-mode map

And also in ess-dev-map on M- prefix. ess-debug-prefix-key is 'meta and
probably should not be changed by users.

git-svn-id: https://svn.r-project.org/ESS/trunk@5502 0bbaf3bd-34e0-0310-bf65-c717079852d4
make ess-tracebug-prefix obsolete

git-svn-id: https://svn.r-project.org/ESS/trunk@5503 0bbaf3bd-34e0-0310-bf65-c717079852d4
rename singlekey into electric

git-svn-id: https://svn.r-project.org/ESS/trunk@5504 0bbaf3bd-34e0-0310-bf65-c717079852d4
cache comint output with periodic flush into user buffer

This makes output printing 5-10 faster.

git-svn-id: https://svn.r-project.org/ESS/trunk@5505 0bbaf3bd-34e0-0310-bf65-c717079852d4
cosmetic

git-svn-id: https://svn.r-project.org/ESS/trunk@5506 0bbaf3bd-34e0-0310-bf65-c717079852d4