WMA indicator is slow

[lkaino]

My program started running quite slow, according to cProfile this is caused by HMA indicator, which in turn uses WMA indicators, which seem to be slow.

I don't know if there's anything that could be done to improve on the performance.

[lkaino]

I improved it in PR: #161. It's a lot faster now, down from 100s to 4s in my test run.