Update BaseEntity.java

This fix the following error :

   "setAttribute: Non-serializable attribute owner"

In the following context :

  - hsql database configuration (updating data-access.properties only)

  - mvn clean install bees:run (cloudbees local run)
Merge pull request #25 from boly38/patch-1

Update BaseEntity.java
removing Serializable because it creates a lot of warnings

App should be as simple as possible for beginners
migrated to latest version of Spring Data, tomcat-jdbc and hsqldb
migrated to Spring 3.2.4
pom:xml: use <dependencyManagement> to force versions of spring-core, spring-context and spring-beans to 3.2.x. instead of exclusions on spring-data-jpa dependency because Maven sometimes pulls both versions 3.2.x and 3.1.x versions of coring-core, spring-beans and spring-context.
Spring MVC should server static resources (*.html, ...) located in src/main/webapp instead of returning "404 Not Found"
fixed a broken link
fixed broken links in readme
fixed one more broken link
migrated to joda-time 2.3
Merge pull request #29 from cyrille-leclerc/fix-spring-version

pom:xml: use <dependencyManagement> to force versions of spring-core, spring-context and spring-beans
Merge pull request #30 from cyrille-leclerc/server-static-resources

Spring MVC should server static resources (*.html, ...) located in src/main/webapp instead of returning "404 Not Found"
migrating to Spring  Data 1.4.1
migrating to Dandelion 0.9.1
Added comments to explain how database dialect is configured #33
Petclinic is now deployed to Cloudfoundry v2. Adding a link to it: http://gopetclinic.cfapps.io/
fixed typo
adding more info about Eclipse validation issue
typo