close tab with middle mouse button
place event in 'onmouseup'
avoid fallthrough in ONMOUSEDOWN
Merge pull request #258 from rstudio/feature/middle-mouse-close-tab

close document by clicking tab with middle mouse button
update running RStudio instance check on Windows installer
look for RStudio anywhere in window title
create new doc on activate source if no active editor
Merge pull request #260 from rstudio/feature/new-doc-on-activate-source

create new doc on activate source if no active editor
refine shortcut handling for completion popup

- No special handling for Left/Right/Home/End
- Tab only accepts for case of continuing a directory completion into a it's subdirectory
don't let pkgs write to stdout on load
restore tab for accepting completions
Merge pull request #261 from rstudio/feature/refine-completion-keys

refine shortcut handling for completion popup
ignore modifier key release in help pane search
add exception guards in critical barrier path
fix completion bug for directory listing
Merge branch 'master' into feature/new-ace