For the left and right positioning use `marginLeft`/`marginRight` `'auto'`

Improves the item render performance

Workaround for Masonic in production builds

Only cosmetic change for use on the computer

!7 introduced changes that were not considered by !8

TODO: Sometimes a bit wonky on chrome.

Use TransformBlock/TransformFinalBlock instead of copying to a MemoryStream. May also have some CPU time benefits.

Display error on fetch error. Fixes #21

Closes #21

See merge request unicorns/bmbf!7