Ticker info can now be fully sourced from Vircurex and CryptoCoinExplorer

* Use of CoinMarketCap is now optional and can be toggled via the TRY_CMC constant
* Error resistance is higher, script smartly can replace all info with info from alternative sources if CMC is down or unused
  * Alternative data sources will also be used in the event that CMC returns 0 for any quantities, in case the Peercoin data from CoinMarketCap goes stale
* Offloaded alternatively sourced data gathering to a helper function, fetch_alternative_market_info(), which now returns the same format as fetch_cmc_market_info()
* If alternative data is sourced, script will also output '*falling back to alt data sources*' which could be checked with a bash script on cron