add loading placeholder

- display `progress` when loading
- watch routing events
handle route errors

- handle 404 route error
- redirect to error when no country data found
- remove console logs
Revert "handle route errors"

This reverts commit e9f007943da5b6bdd6b0bc391e0a74526d04b543.
remove console logging
handle 'country not found' error

- controller checks country data
- model handles undefined objects (capitals)
- new view for country not found
table row striping
simple pagination

- limit to 20 results per page
- display result number in table
- back/next buttons to move through pages
restore padding on table cells

restore the padding on the left and right edges of the table. this will
indent table text but the alignment will be kept by background colours
on the table rows and the width of the border under thead