#18: Fixed comparison issue on Python 3.x in "raiseAppropriateException" caused by float division being applied instead of floor division.
ID for SteamUser should be an int, not a string.
Catch APIExceptions inside __repr__ and revert to "safe" __repr__ so that it wouldn't throw.
#18: Added "shims" for string sanitation in __repr__. On Python 2.x we need to convert it to ASCII, while on Python 3.x we need to leave it as-is. On-load, "core._shims" is populated with the functions meant for the running Python version, and these functions are -- in turn -- used internally throughout the code. This allows for version-agnostic syntax while the underlying code actually handles backwards compatibility and such.
In SteamUser.friends:
 - Added conversion for "id_player_map.keys()" to a "list" object to fix #17, where on Python 3.x "dict.keys()" would return a "dict_keys" object that doesn't support indexing.
 - Removed chunk-division for "GetPlayerSummaries" calls as requests 2.3.0 supports TCP fragmentation for requests.