[GB] check installed deps & log user friendly error, fix #2455

[askmike]

If a user has not installed Gekko Broker, Gekko will now log a more user friendly error like:

➜  gekko git:(hotfix/gb-check-installed-deps) ✗ node gekko -c cer.js

    ______   ________  __    __  __    __   ______
   /      \ /        |/  |  /  |/  |  /  | /      \
  /$$$$$$  |$$$$$$$$/ $$ | /$$/ $$ | /$$/ /$$$$$$  |
  $$ | _$$/ $$ |__    $$ |/$$/  $$ |/$$/  $$ |  $$ |
  $$ |/    |$$    |   $$  $$<   $$  $$<   $$ |  $$ |
  $$ |$$$$ |$$$$$/    $$$$$  \  $$$$$  \  $$ |  $$ |
  $$ \__$$ |$$ |_____ $$ |$$  \ $$ |$$  \ $$ \__$$ |
  $$    $$/ $$       |$$ | $$  |$$ | $$  |$$    $$/ 
   $$$$$$/  $$$$$$$$/ $$/   $$/ $$/   $$/  $$$$$$/

  Gekko v0.6.5
  I'm gonna make you rich, Bud Fox. 


2018-08-20 15:26:46 (INFO): Setting up Gekko in realtime mode
2018-08-20 15:26:46 (INFO): 
2018-08-20 15:26:46 (INFO): Setting up:
2018-08-20 15:26:46 (INFO):    Trading Advisor
2018-08-20 15:26:46 (INFO):    Calculate trading advice
2018-08-20 15:26:46 (INFO):    Using the strategy: DEBUG_single-advice

The following Gekko Broker dependencies are not installed: [ binance, bitx, coinfalcon, gdax, kraken-api, gekko-broker-poloniex, gekko-bittrex ].

You need to install them first, read here how: https://gekko.wizb.it/docs/installation/installing_gekko.html#Installing-Gekko-39-s-dependencies

Or with the UI (in the terminal)

  <-- GET /api/configPart/paperTrader
  --> GET /api/configPart/paperTrader 200 15ms 132b
  <-- POST /api/startGekko

The following Gekko Broker dependencies are not installed: [ binance, bitx, coinfalcon, gdax, kraken-api, gekko-broker-poloniex, gekko-bittrex ].

You need to install them first, read here how: https://gekko.wizb.it/docs/installation/installing_gekko.html#Installing-Gekko-39-s-dependencies

Showing them in the UI is too much work, I'll make sure that happens in the next UI I'm building.

[StevenHop]

Great! Thank you very much!