ENH?: __repr__ method for Index objects
It often happens that I print a MultiIndex object (whether on purpose or not) which leads to flooding my interpreter and makes it unresponsive for a couple of seconds since often the length of my indexers exceeds 500-1000k. I was thinking about adding a neat `__repr__` for Indexers that summarizes levels + length or just omits what's in the middle once a certain length is exceeded. It seems this has not been tackled so far when looking at the current master, but please feel free to close this issue if this is a dupe (checked but did not find anything related). Any pointers are welcome.
