Fix for non-canvas tile rendering at large size

In USE_CANVAS==false mode, wrapped tile img elements in div elements to
allow them to be rendered larger than their containing element without
being stretched.
Whitespace fix
Punctuation fix
Merge pull request #264 from msalsbery/Tile-Render-Bug

Fix for non-canvas tile rendering at large size
Changelog for #264.
Merged changes from master