EDIT: RStudio developer Jonathan points out that this is no longer necessary since the new version of RStudio is missing, which has no problem dependency. You can get this version here: https://www.rstudio.com/products/rstudio/download/preview/
For a similar solution, but which contains additional instructions to ensure that legacy packages are not updated, see the alternative below. Thanks to Mike Williamson for the excellent instructions reproduced below:
1) Get the latest version of R Studio Daily Build here , although note that it is not necessarily stable.
2) Install by changing the name of the package to the one you downloaded - perhaps the easiest if you go to the Downloads directory and you probably find that the packages are missing:
sudo dpkg -i rstudio-1.0.124-amd64.deb
3) Download the missing packages (the absence of which leads to installation failure):
wget http://ftp.ca.debian.org/debian/pool/main/g/gstreamer0.10/libgstreamer0.10-0_0.10.36-1.5_amd64.deb
wget http://ftp.ca.debian.org/debian/pool/main/g/gst-plugins-base0.10/libgstreamer-plugins-base0.10-0_0.10.36-2_amd64.deb
4) Install them:
sudo dpkg -i libgstreamer0.10-0_0.10.36-1.5_amd64.deb
sudo dpkg -i libgstreamer-plugins-base0.10-0_0.10.36-2_amd64.deb
5) Make sure they are not overwritten during the next software update:
sudo apt-mark hold libgstreamer-plugins-base0.10-0
sudo apt-mark hold libgstreamer0.10
6) Install RStudio (changing the name to the downloaded version):
sudo gdebi rstudio-1.1.5-amd64.deb
7) Launch RStudio:
rstudio