Dividend name

[maxsam4]

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?

Enhancement

What is the current behavior?

Dividends are unnamed

What is the new behavior?

Dividend have a name

Does this PR introduce a breaking change?

(What changes might users need to make in their application due to this PR?)
Need to pass Dividend name when creating a Dividend.

Any Other information:

1. Apparently Sublime added whitespace changes to the whole contracts :/. Add ?w=1 to the URL to see the diff with whitespace ignored (213b318?w=1).
2. I made _createDividendWithCheckpointAndExclusions an internal function to save gas when being called from public functions. public -> public function calls require all the parameters to be copied into memory again while public -> internal will just pass on the reference.
3. I am unable to run tests on my local machine for now so using travis for testing.

Fixes #295

[adamdossa]

@maxsam4 Looks good to me - only comment is please could the function:
_CallERC20DividendDepositedEvent
be renamed to:
_emitERC20DividendDepositedEvent

[satyamakgec]

I am not a big fan of bytes32 but if we can replace the datatype to bytes32 for name then we can indexed it in the events that may useful for the dApp team.

[pabloruiz55]

looks good! Needs @satyamakgec 's approval