Incomplete migration of BasicLanguage.strings to new format.
Important style changes. Will for sure break some things.

* viewtype= now replaces ltype= inside of the <html> and <body>
elements to describe the actual view type.
* ltype= is no longer appended to the first nested <p> of a message
with a sender. Instead, mtype= is appended to the top-most div. The
mtype= (member type) value contains either “myself” or does not exist.
* The ltype= attribute of .sender has been replaced with the name mtype=
* The nick= attribute of .sender has been replaced with the name
nickname=
* type= is no longer included anywhere in the default styles. This
attribute has been documented as deprecated for several versions.
* ltype= is used in the scripts.js files of the default styles. I
mistakenly used type=