Update src/header.js

Closure to cache document, Math, undefined -- should result in a very slight performance improvement and smaller minified size.
Update src/footer.js

Closure to cache document, Math, undefined -- should result in a very slight performance improvement and smaller minified size.

(note that undefined doesn't need to be passed in as a parameter -- by default any parameter not set will have the value of undefined)
Update src/header.js

Prevent multiple instantiations of the plugin
Box plot size is now correct for small (max - min) values.

Using a unit "offset" of 1.0 caused box plots to fail to fill the
canvas.  This change only sets to offset to 1.0 if the ( max - min )
would otherwise cause a division by zero.  With this correction, box
plots now correctly scale to the canvas width.
Fix issue #50 (bug) with chrome's subpixel rendering not showing tooltips when mouseenter from left
Add Bin Labels To Tooltips
Add prefix to other plot types (except Box); add header info.
Avoid load errors with document.namespaces in IE
Avoid load errors with document.namespaces in IE
Merge remote-tracking branch 'remotes/ssclift/master'
Merge remote-tracking branch 'remotes/timtucker/patch-4'

Conflicts:
	src/vcanvas-base.js
Merge remote-tracking branch 'remotes/timtucker/patch-3'
Merge remote-tracking branch 'remotes/timtucker/patch-2'
Merge remote-tracking branch 'remotes/jledoux/master'
tweaked the google chrome render fix
code cleanup
whitespace police: TAB --> SPACES + cleanup