EMA 55 Crossover

Basically what this does is to flag when EMA 55 crosses over EMA 8, 13, 21, and 200. This strategy was described by @Philakone on this tweet , but I'm not really sure if this is the correct strategy he described.

版本注释:

Fixing typo.

版本注释:

After reading the comments it looks like EMA 200 shouldn't be taken in count for the crossover so I removed it from the crossover logic.