Fixed errors / problems and replaced mysql by H2 in library sample

Hi, 
you suggested me your lib some time ago on stackoverflow. 

I tried the sample but needed to fix some parts before I could get them run:

- The jcalendar is not contained in maven central, so one has to manually download and install it to the local repository. I added the instructions how to do this to the README and updated the pom, as the version 1.1 is not available any more

- I was too lazy to install a mysql db just for running a sample, so I replaced mysql by H2 and configured hibernate such that everything runs out of the box, including schema creation. (I did not check your original sql file for creating the database, so I'm not sure if there is something missing, as the schema creation only relies on the annotations, but the app seems to work fine). Your choice if you want to take this one or not.

- Finally I updated the README to reflect the changes of mysql to H2, and also I corrected the instructions to run the app as the version of the jar was a different one and hence the program wouldn't run on my computer. I used an asterisk.