Retrieving blobs not working after local dev server has been restarted about app-inventor HOT 9 CLOSED

This is due to a known bug in App Engine: 
"http://code.google.com/p/googleappengine/issues/detail?id=5449".

We reported the bug to the App Engine team.  They tell us they fixed the bug 
(with the data Liz gave them), and the fix will be in release 1.6.2.

We need to add a warning if the dev server is started with a version < 1.6.2 
(which has not yet been released).  We should also test that the bug is indeed 
fixed with 1.6.2.

Ellen,
You can use Server.isProductionServer to tell whether our server code is 
running in appengine (true) or on the local dev server (false).
To get the version of the local dev server, call 
System.getProperty("com.google.appengine.runtime.version"). It returns a String 
like "1.6.1".
-Liz

For reference, a user will see this in the following way, if using the 
dev-server:

- build project A
- switch to another project
- come back to project A:  sometimes the assets won't appear (e.g. am image) 
sometimes the project won't build.

Release 1.6.2 is now out and at least one user reports that the problem of 
blobs going away between reloads seems to be fixed. We should probably still 
test it, and then close this bug.