MATM changes

[comeonbuddy]

Please check if the PR fulfills these requirements

• The commit message follows our Submission guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce?

• Removed all the blocking related functions and events in MATM
• Given a single address, anyone is able to see a list of all active approvals from/to that address
• Improved MATM to allow allowances and expiryTimes to be changed for existing approvals.
• As an issuer, you are able to add/revoke in batches (using a multi approach)
• As an issuer, you are able to add a description to a manual approval.
• Anyone is able to see a list of all active approvals

Does this PR introduce a breaking change?

Yes

Any Other information:

[satyamakgec]

Changes are looking fine to me.
@comeonbuddy you don't need to remove /*solium-disable-next-line security/no-block-members*/ this from the code it only used for linting :)

[maxsam4]

Still need to review logic. Only completed style review currently.

[maxsam4]

The code looks good, Just some minor things that can be optimized.
Test cases need to be fixed/added.

[VictorVicente]

Edited title and description to include all new MATM changes

[coveralls]

Coverage decreased (-0.3%) to 97.746% when pulling ad29c1b on remove-blocking-MATM into f2bd23a on dev-2.1.0.