Please consider adding a mode to enable and disable abbreviations. Currently, 
one can disable them but only with the command ":abc <buffer>", which deletes 
all the abbreviations and is also difficult to figure out (":abc" by itself 
doesn't work). There is a recent discussion thread on the user's list covering 
this problem. I am thinking along the lines of ":set noabbrev" and ":set 
abbrev".