using iron-list

[julianmanandhar]

@tyohan We've been having issues working with iron-list in the shuvayatra-feed element.
It just shows first 3 elements of the list even if there is available space for more than 3 elements. The rest of the list items are not visible but do exist on the screen when we use inspect-tools.

As a work-around, we've implemented the list using dom-repeat for now, which is less effective for long lists. Could you take a look at it and inform us if you can come up with something. Thanks.

[tyohan]

@julianraj for iron-list, the item must have a fixed height. So you need to set on css style how many pixel the height will be. Because it's need to calculate the viewport size and show items based on the size. So you need to make all item will have fixed height, even its has different type.