method init will try to load the file app.properties from the binnary folder, getValue first will try to get the value from datastore and if it does not exist will try it from app.properties loaded, finally using method copyPropertiesIntoDatastore it is possible to save values of app.properties in the datastore
rename ResponseFilter to Error500Filter and move the configuration from web.xml to error500.properties, also this filter now send all the request information
Merge branch 'version2' of https://github.com/intelygenz/igzcode-gae into version2

Conflicts:
	src/main/java/com/igzcode/java/gae/util/ConfigUtil.java