ignore all errors only for no subtitles
update configuration for tmux 1.8

tmux 1.8 has been emerged for two months, and even 1.6 for very long
time, but I was still using ~/bin/tmux, didn't realize that it was a
custom built binary, older, older version. Now I finally realize why
some options were not recognized.
don't create or split window with current pane's current directory
make activity indication less intrusive in status bar
move options to config file
enable math role and directive for MathML output
fix for latest vcprompt code