Demo app instantly crashes

Just downloaded form master, using Xcode 9.1 and Swift.

I receive this error:

```
2017-11-28 14:52:57.129224+0000 ChartsDemo-Swift[592:395114] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key chartViews.'
*** First throw call stack:
(0x18638dd04 0x1855dc528 0x18638d9cc 0x186c9a780 0x19002d010 0x18629b058 0x18fd53628 0x18fd5b1c4 0x18fa2cf4c 0x18f833654 0x18fa2bdb4 0x18fcc26b4 0x18ff96c78 0x18fcc2318 0x18fcc2b88 0x19043e4b8 0x19043e35c 0x1901b0294 0x1903470ac 0x1901b0144 0x18ff962d8 0x18fa2a61c 0x18fe3887c 0x188a39758 0x188a42060 0x1020b545c 0x1020c1b74 0x188a6d9f4 0x188a6d698 0x188a6dc34 0x1863362e8 0x186336268 0x186335af0 0x1863336c8 0x186253fb8 0x1880ebf84 0x18f8282f4 0x100d047cc 0x185d7656c)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)
```