v0.6.4

Minor hotfix release.

Unfortunately a few minor bugs were present in the previous release, this includes fixes for:

• Bitfinex importing candle inconsistancy (5cad680 & #2354 - @askmike)
• Broken Binance paper trader (dbd39ab - @askmike)
• Live/paper trading chart renders wrong dates (#2360 - @askmike)

More changes:

• [UI] Make sure all assets have relative paths (#2359 - @askmike)
• [DOCS] Fix function name for stratNotification (#2356 - @ptdev)
• [GB/LUNO] rename bitx to luno (#2352 - @hiyan)
• [GB/BFX] Don't consider all 500 errors retryable (afefb14 - @askmike)
• [GB/BINANCE] Return fee as percent, not fractional (17e8a8c - @askmike)