Added flag delegation

[IanMendozaJaimes]

Fixes #406

• Added flag delegation
• Added tables delegators in accounts

Note

I added two generic functions inutils:

• Send deferred transaction
• Delete a table (for use it in the reset function)

I only added those functions to the actions involved in this issue. I think it could help make the contracts look cleaner. Please let me know what you think, I could refactor some contracts to try or if you feel it's not needed I can remove it and change it for the normal way.

Modified contracts:

• [x] Accounts

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