Lots of bugs fixed!!

Sorry i've been busy lately.. I just fixed this extension. please try again.

now if you try my another extension : mootensai/yii2-enhanced-gii it should be working properly.

newest fix are :

1. fixing many-many update
2. fixing delete the last record in a detail set. (for many-many & has many)
3. ignore empty post
4. add error for data integrity when deleting

To do

1. add feature for one-to-one