dev branch: Config Paths only work with `./` prefix

[EvanLovely]

I'm seeing an issue when using paths in config that do not start with ./: you can't do absolute paths or relative paths that start with ../.

It appears to be from the use of file.substring(2) as an argument used in builder/patternlab.js:93 like this:

pattern_assembler.process_pattern_iterative(file.substring(2), patternlab);

[EvanLovely]

Absolute paths that would start with /Users/Evan/ end up being processed with this at beginning: sers/Evan/

[EvanLovely]

This affected my testing and hopeful use of #216

[bmuenzenmeyer]

Thanks Evan.

Hmm I thought I tested this quickly with source being a directory up, but you are right I made it relative - so clearly this needs a closer look before it lands or clearer constraints.
Will add this to : #220

[bmuenzenmeyer]

Now that #230 is in dev, it's time to test. Will do so tonight I hope

[bmuenzenmeyer]

Tested this. Looks great!
Like usual, this will close when it reaches master