When ActiveJDBC cache is used, both EHcache v2 and 3 need to be on the classpath

[ipolevoy]

if just EHcache v3 is on the classpath, it results in the exception below.

The class net/sf/ehcache/ObjectExistsException si only part of Ehcache 2.

java.lang.NoClassDefFoundError: net/sf/ehcache/ObjectExistsException

	at java.base/java.lang.Class.forName0(Native Method)
	at java.base/java.lang.Class.forName(Class.java:375)
	at org.javalite.activejdbc.cache.QueryCache.<init>(QueryCache.java:52)
	at org.javalite.activejdbc.cache.QueryCache.<clinit>(QueryCache.java:36)
	at org.javalite.activejdbc.Registry.cacheManager(Registry.java:85)
	at org.javalite.activejdbc.cache.CacheEventSquasher.close(CacheEventSquasher.java:85)
	at org.javalite.activejdbc.Model.save(Model.java:2747)
	at org.javalite.activejdbc.Model.saveIt(Model.java:2667)
	at org.javalite.activejdbc.Model.addOne2ManyChild(Model.java:2571)
	at org.javalite.activejdbc.Model.add(Model.java:2548)