doc: prefix StellarSdk namespace for TransactionBuilder, Account & Operation and change sequence number to string in Account constructors
doc: prefix StellarSdk namespace for TransactionBuilder, Account & Operation and change sequence number to string in Account constructors

johansten/js-stellar-base,johansten/js-stellar-base,stellar/js-stellar-base,johansten/js-stellar-base,stellar/js-stellar-base