Several of the columns directly assigned member variables that ought to have

been included in __init__ instead. While this was perhaps slightly more

readable, it meant that the Column.__init__ method couldn't operate on them.
This change moves all those parameters into the __init__ calls. It also splits

the "To Me" column into using detailed_label_html and detailed_label, to

dovetail with my djblets change that fixes the sort order in the column

selector.

Looked at the column selector and saw that everything was in alphabetical

order, even when the column included HTML or other entities at the beginning of

the text.