Fix docs/README.md
Fix docs/README.md

Invalid tokens: github had made some changes the past months, the old style is not rendering at all, so I fixed that for you. 

Other contributors can do the same for all of the project's documents.

Thanks.
davecgh/btcd,Roasbeef/btcd,ppcsuite/ppcd,Roasbeef/btcd,dajohi/btcd,aakselrod/btcd,tb00/btcd,btcsuite/btcd,Stash-Crypto/btcd,dajohi/btcd,Stash-Crypto/btcd,ppcsuite/ppcd,cqswxj2013/btcd,wallclockbuilder/btcd,dajohi/btcd,btcsuite/btcd,cqswxj2013/btcd,tb00/btcd,wallclockbuilder/btcd,davecgh/btcd,ltcsuite/ltcd,aakselrod/btcd,ltcsuite/ltcd