Fixed typo in env variable

MY_DATOMIC_USERNAME was used twice.
Using /bin/echo

At least on my Mac, only `/bin/echo` understands `-n`. With just `echo`, I get a literal `-n` in the properties file and an error reading the license.
Fixed two TODOs
Updated jdk and datomic versions
Updated jdk version
Updated various dependencies
Invalid Datomic URI without database name

For some reason there is no database name in the `DATOMIC_URI` in the template. This results in a failure to deploy the web application. The error can be seen in `/var/log/tomcat7/localhost.<date>.log`:
```
java.lang.IllegalArgumentException: :db.error/invalid-db-uri Invalid database URI datomic:ddb://eu-west-1/datomic_demo_staging/
```
Now handling BSD stat too

BSD stat (default on Macs) has a different flag for timestamp: `-f %m` instead of `-c %Y`.
The command may fail when determining which one to use, so I moved the `set -e`.
Also fixed the update-stack script.
Merge pull request #2 from ulsa/patch-1

Fixed typo in env variable
Merge pull request #4 from ulsa/patch-3

Fixed two TODOs
Merge pull request #6 from ulsa/patch-5

Updated jdk version
Merge pull request #7 from ulsa/patch-6

Updated various dependencies
Merge pull request #5 from ulsa/patch-4

Updated jdk and datomic versions
Merge pull request #3 from ulsa/patch-2

Using /bin/echo
Merge pull request #11 from ulsa/patch-10

Now handling BSD stat as well
Merge pull request #10 from ulsa/patch-9

Invalid Datomic URI without database name