Added OneToManyRelation and ManyToManyRelation table helpers. Usage samples are located in according test classes.
Added static saveMultiple(..) method in Model class.
Modified isModel() method to allow fields of Model type, checking if table class is abstract in scanForModelClasses() instead.
Merge branch 'master' of https://github.com/nemezis/ActiveAndroid

Conflicts:
	tests/src/com/activeandroid/test/model/ManyToManyTest.java
	tests/src/com/activeandroid/test/model/OneToManyTest.java