Replace icon template with new style and multiple densities.

Replace icon template with new style and multiple densities.

The icon in the templates of ADT was medium density only.
I added new densities (high and low), as well as updated to
the new Eclair style. Also added a version for Ant project.

Updated ADT and sdklib to deal with creating new projects
with all 3 icons.

In case of Ant project, this is done only if the icons
are present in the target platforms.

For ADT, this is done only if the project target donut
or later. Older project still have only one icon located
in drawable/

Change-Id: I77069a1e4902ef395d490526aabc40a26e33d4ca