Fix #453: Prevent text from wrapping in editor elements

[bryphe]

Issue: In some cases, the spans for text content are sized just a bit too small, causing the text to wrap

Defect: It seems that in some cases, with fractional fonts, there are fractional errors in the calculation that cause the element to be sized just a bit too small. This does not reproduce for all fonts / environments.

Fix: Experimented with a few different ways to fix this:

• Add a buffer to the element (using Math.ceil for the calculation). This didn't work in all cases
• Add whitespace: nowrap to the elements to prevent wrapping

The latter fix seemed to work reliably, and there was not a performance regression based on my testing, so I went with that scoped fix.

[bryphe]

Fix #453