Update misc.js

add parseUnit function to normalize mm,cm,in,pt,pc to pixels.
res is setted to 96dpi is not real screen resolution dependant.
Update parser.js

Use parseUnit to normalize pt,pc,mm,in,cm to px.
Update parser.js
Update misc.js
Update misc.js

added missing space.
Update misc.js
Update misc.js

it had some problem with len of string 0 and slicing from 0 to -0 , or calculating len of ''.
now is ok, rects went crazy and i didn't notice.
Update misc.js

some more polishing
Update parser.js
Update HEADER.js

Moved fabric.DPI to proper file.
Update misc.js

some more polishing, for me and for toFixed.
Merge pull request #1491 from asturur/basic-unit-support

Basic unit support