Added check if columns with null values are attempted to be added

[nadenf]

No description provided.

[nadenf]

public class Goal {
@NoSqlOneToMany
public List cards;
}

Will throw a NullPointerException when saving.
com.alvazan.orm.impl.meta.data.MetaToManyField.translateToColumnImpl(MetaToManyField.java:164

Which is this line in my version of Playorm:
//now process all the existing columns (we can add same entity as many times as we like and it does not get duplicated)
for(PROXY proxy : toBeAdded)

[nadenf]

Note: only take the first commit. Not sure why it pulled in the other changes.

[deanhiller]

sorry, was on vacation, should be puling it this week.