Added ETF fundraiser

Open-ended ETF fundraiser based on NAV value, with divisible and variable number of shares.
Update README.md

Added version updated to 4.6, encompasses PRs for ETF, automated dividends, standardized bets, escrow-backed fund creation/redemption.
Appended Dividends for Automation

Specified Divident Addresses with a regular pay-out time interval.
Standardized CDFs

Needs more chiseling on fields and logic to automate settlement (hinges on dividend function), escrow re-capitalization when trading an already issued contract, and the option to automatically roll-over a winning contract by issuing a dividend split between MSC and a new contract.
Added images
Open-ended Fundraiser

Allows ETF-style funds.
Fixed Formatting
Merge branch 'Open-endedFundraise' of github.com:patrickdugan/spec into patrickdugan-Open-endedFundraise

Conflicts:
	README.md
Merge branch 'patrickdugan-Open-endedFundraise'