Update README.md

Generally made the readme a bit more verbose and informative while hopefully conserving the funny bits.

I removed the link to Wikipedia referencing the Dogecoin block rewards and included both the old and current block reward scheme in the readme because this is something people expect to find in the primary readme of a project in my opinion (not to mention that Wikipedia should ideally have an authoritative document saying so and which isn't the source code, otherwise this sort of thing tends to happen: https://xkcd.com/978/ ;-))

Just my 2 Doge. :D
Bring back the shibeface!
Port custom shibeface from b14d83aabd45bafba5e9329fec95b58d0073de19
Fix intendation

Stupid editor!
s/bit/doge
Corrected coin maturity time shown in UI.
Merge pull request #437 from rnicoll/1.7-dev-maturity

Corrected coin maturity time shown in UI.
Merge pull request #436 from langerhans/1.7-dev-shibeface

Bring back the shibeface!
Revert "Hardcode testnet for first alpha release."

This reverts commit b16685ca0d0e00424281e0af2f346ff60ace53bf.
Change the lookup span modulo constant to something smaller

Why? Not really sure, but whatever.

Conflicts:

	src/rpcmining.cpp
Clarified label on constant containing difficulty change interval.
Removed wallet upgrade code inherited from Bitcoin/Litecoin, as it does not apply to Dogecoin
wallets (too new at base.
Merge pull request #439 from rnicoll/1.7-dev-network-hashps

Update difficulty change interval constant to match 1.6
Merge pull request #442 from rnicoll/1.7-dev-upgrade

Removed wallet upgrade code inherited from Bitcoin/Litecoin
Update README.md
Update README.md
Update README.md
Merge pull request #427 from jwiechers/patch-2

Update README.md