* cmd/utils: make goerli the default testnet

* cmd/geth: explicitly rename testnet to ropsten

* core: explicitly rename testnet to ropsten

* params: explicitly rename testnet to ropsten

* cmd: explicitly rename testnet to ropsten

* miner: explicitly rename testnet to ropsten

* mobile: allow for returning the goerli spec

* tests: explicitly rename testnet to ropsten

* docs: update readme to reflect changes to the default testnet

* mobile: allow for configuring goerli and rinkeby nodes

* cmd/geth: revert --testnet back to ropsten and mark as legacy

* cmd/util: mark --testnet flag as deprecated

* docs: update readme to properly reflect the 3 testnets

* cmd/utils: add an explicit deprecation warning on startup

* cmd/utils: swap goerli and ropsten in usage

* cmd/geth: swap goerli and ropsten in usage

* cmd/geth: if running a known preset, log it for convenience

* docs: improve readme on usage of ropsten's testnet datadir

* cmd/utils: check if legacy `testnet` datadir exists for ropsten

* cmd/geth: check for legacy testnet path in console command

* cmd/geth: use switch statement for complex conditions in main

* cmd/geth: move known preset log statement to the very top

* cmd/utils: create new ropsten configurations in the ropsten datadir

* cmd/utils: makedatadir should check for existing testnet dir

* cmd/geth: add legacy testnet flag to the copy db command

* cmd/geth: add legacy testnet flag to the inspect command

* add istanbul and muirGlacier to genesis states in README

* remove muirGlacier, relocate istanbul

* Accounts in alloc field must already exist

Note that accounts in alloc field must already exist, as pointed out by Simeon Vanov in https://gettoshare.com/2017/10/30/how-to-use-genesis-json-alloc-property/

* Change wording per PR review comment

* README: minor fixups

* Change chainId in genesis block to 8888 from 0 

Change chainId in genesis block to 8888 from 0 per Moriteru in https://ethereum.stackexchange.com/a/28082/40230.

* Replace 8888 with “<arbitrary positive integer>”

Per PR review, replace Moriteru’s arbitrary positive integer 8888 with “<arbitrary positive integer>” in chainId field.

Changed http:// to https:// on JSON-RPC link in README.md

Signed-off-by: YaoZengzeng <yaozengzeng@zju.edu.cn>

* eth: added travis build status for master branch

* README: fix travis badge order, link to CI

* README: add goreportcard.com badge to Readme

* README: fix double github.com

* Remove --fast flag and clarify default

`--fast` is no longer a flag it's `--syncmode "fast"` and that is the default

* Remove --cache flag

--cache=512 is no longer required as of 1.8 as the default has been increased

* README: Minor cache amount fix, mention Rinkeby

missing period at line 119

README: change heading to "Go Ethereum"