rename BareConstructor to SuperclassBare

'cos the pre-existing and well-named `Bare` is totally also a
constructor

also clarify SuperclassBare's comment to be more specific
Merge pull request #14 from laughinghan/SuperclassBare

rename BareConstructor to SuperclassBare
Update makefile for UglifyJS2, ignore vim undo files
Merge pull request #15 from danro/master

Updated Makefile for Uglify2, npm ignore, Mac OSX + perf notes.
v3.0.2
minifier optimization: return a function expression
Add C.p as an alias for C.prototype
v3.1.0
kill mixins, replace with .extend()
v4.0.0
update the readme for replacing .mixin with .extend