Define a event criteria about contracts HOT 5 CLOSED

I've created the PR #14 adding some events as a result of the TOB audit. For now they are:

* Hermez (InstantWithdrawManager.sol) -> UpdateWithdrawalDelay

* Hermez (InstantWithdrawManager.sol) -> UpdateBucketsParameters

* Hermez (InstantWithdrawManager.sol) -> UpdateTokenExchange

* Hermez (InstantWithdrawManager.sol) -> SafeMode

If @arnaubennassar @ed255 @krlosMata you think there are some other missing events or want to change some of them, I can add them to this PR.

The two events that I was missing were about WithdrawalDelay and Buckets. I see in the PR that now there are events for those two. Nevertheless I think the event for buckets could be extended! I'll leave a comment in the PR explaining this.

EDIT: Link to the comment in the PR #14 (comment)

from contracts.

• I think it is useful to have events for those parameters that the governance can update. In this way you avoid to do polling to detect a variable update.

As far as I see in the Hermez.sol there are already events for those variables:

• UpdateFeeAddToken
• UpdateForgeL1L2BatchTimeout

from contracts.

Here's an incomplete list of public variables that don't have events:

• Hermez (InstantWithdrawManager.sol) -> withdrawalDelay
• Hermez (InstantWithdrawManager.sol) -> buckets

from contracts.

I've created the PR #14 adding some events as a result of the TOB audit. For now they are:

• Hermez (InstantWithdrawManager.sol) -> UpdateWithdrawalDelay
• Hermez (InstantWithdrawManager.sol) -> UpdateBucketsParameters
• Hermez (InstantWithdrawManager.sol) -> UpdateTokenExchange
• Hermez (InstantWithdrawManager.sol) -> SafeMode

If @arnaubennassar @ed255 @krlosMata you think there are some other missing events or want to change some of them, I can add them to this PR.

from contracts.

We need to add the new hashGlobalInputs to the event

from contracts.