Updates to SDK troubleshooting doc, per bug 2315781.

Describes work-around for these problems: Sometimes you
can't view manifest files within Eclipse; you can't run
the GestureBuilder sample on the emulator or uninstall it
from the emulator.

Bug: 2315781
Change-Id: Ia36d8e74a9fccd106ce2cc5e9451846aacba9da4