Make hparams hyperparameter & metrics lists sorted

Currently when using the hparams functionality, the list of hyperparameters metrics do not appear to have any sort of sorting on them. They're just in there randomly. This includes:

• The "Hyperparameters" pane in the top left
• The "Metrics" pane in the middle left
• The "Sort by" dropdown in the "sorting" pane on the left
• The column headers in table view
• parallel coordinates view
• etc.

This makes it very difficult to find the parameter you're after, as it could be anywhere.

I think the likely acceptable option would be to make them alphabetically sorted.
Alternatively, though I think less preferable, would be to keep order they were added to the dictionary (the one passed to the callback) within python (since python dictionaries are insertion-ordered as of 3.6).