gerbot updates, candles for 30 days chart

Now SE API returns open and close price and gerbot will draw 30 days candlesticks chart for you, ^chart30 symbol. Rest of the charts 7 days and total I left unchanged. The display of charts is broken for some tokens anyway, due to high differences in prices.

Spreadsheet masters can get daily data with open and close price using ^historycsv symbol.

^buyers and ^sellers commands are not supported anymore, requests to the API not returning names of users selling/buying tokens.

You can also link your steem account with gerbot using ^link. I prepared that for any discord based tokens distribution. Not sure where to go from that, I can do airdrops on that or customer service/beta testing by users for users with rewards.

Gerbot has plenty of unfinished features like live curation system with rewards for users voting content on discord, with automated steem voting from a special steem account on certain rules or just table with content chosen by people to vote. Am just not sure if anyone needs something like that :)