Rename 'chair' to 'reviewer'
Rename 'chair' to 'reviewer'

The XBL review, and probably the Sync and Storage review will separate
the roles of the chair and reviewer. Renaming 'chair' to 'reviewer' is
step 1.

joewalker/firefox-browser-architecture,joewalker/firefox-browser-architecture,Mossop/firefox-browser-architecture,Mossop/firefox-browser-architecture