Increased story description size

Stories can now have much longer descriptions.
The database is updated with the new column length at startup.
Created a simple framework for handling schema updates

Classes in the dbupdate package that extend DbUpdater and have the
annotation DbUpdate will get registered as schema updates and will
be run at startup. The first update increases the length of story
descriptions.
Enabled Hibernate level 2 cache

This should give some performance improvements.
Merge branch 'master' into hibernate-cache

Conflicts:
	src/main/java/com/sonymobile/backlogtool/Story.java
	src/main/java/com/sonymobile/backlogtool/dbupdate/DbUpdater.java
	src/main/java/com/sonymobile/backlogtool/dbupdate/SchemaVersion.java
	src/main/java/com/sonymobile/backlogtool/dbupdate/UpdateVersion1_2.java
	src/main/webapp/resources/js/scripts.js
Small configuration changes for Ehcache
Merge pull request #86 from fredrikpersson/hibernate-cache

Enabled Hibernate level 2 cache