Improve hot reload

Here is an enhancement of  springloaded 

1) Reload new class - See JHipsterFileSystemWatcher class
A new VM option needs to be set. (-DtargetClassFolder=/Users/jmirc/0-Personal/demo-jhipster/target/classes) This is the folder where the classes are compiled. We can work to generate a file using maven to set this information, or to find another way.

2) Improve the spring loaded