md-list-item needs improved treatment of text overflow

[hanthomas]

This issue is being created per suggestion from @marcysutton in issue #2438. The resolution in #2438 while good, reveals a new problem when a list item contains long text. Because line-height of the text DIV is set to 3.6rem, it causes the text to wrap with a ton of vertical white space. It would be nice if we had some explicit control over text treatment in list items (other than simply overriding the styles). Basically, I see a need for 1) wrapping text (but in a nice way with minimal vertical space) or 2) truncate the text with either ellipses or none.

[rschmukler]

Duplicate of #2199, closing this one.