* Update to version 1.8.7 of ElectrumX
* Upgrade to Python 3.7
This is suggested in the release notes of ElectrumX:
"It is strongly recommended you upgrade to Python 3.7, which
fixes bugs in asyncio that caused an ever-growing open file count
and memory consumption whilst serving clients. Those problems
should not occur with Python 3.7."
* Remove .py from the file to execute
* Rename Bitcoin to BitcoinSegwit as required by ElectrumX
* Travis to check version from new path
