Filepaths with spaces causes crash in context menu

[jonnyhyman]

In the editor.Interface.textChange function, when doing
with open(self.file,'r') as f:

self.file gets shortened if there is a space in the name, and is being opened by context menu.

[jonnyhyman]

This appears to be an issue during installation - in that when we assign the command >> "C:\Python3x-yy\Lib\site-packages\makepython\makepython.exe" %L to the "HKEY_CLASSES_ROOT\Python.File\Edit with Make Python\command" registry entry,

%L seems to lose information after spaces.

[jonnyhyman]

FIX: Changing registry entry to "C:\Python3x-yy\Lib\site-packages\makepython\makepython.exe" "%L" fixes the problem. Updating installer\editor_installer.py and pushing an update...