Fix and simplify resolveToFullPath_

[ussuri]

Bug fixes:

• resolveToFullPath_('/', '.foo') would return '/foo' - not '/.foo'
• resolveToFullPath_('/', 'a/b/../../foo') would return '/a/foo' - not '/foo'
• resolveToFullPath_('/', 'a////b////foo') would return '/a//b//foo' - not '/a/b/foo'
• Some others.

The jsbin for the new version is here: http://jsbin.com/fiqogurowo/2/edit?js,console

[ebidel]

• resolveToFullPath_('/', '.foo') should resolve to /.foo. ".foo" is a valid dot file name, not a folder
• `resolveToFullPath_('/', 'a/b/../../foo') should return "/foo"
• In unix, it resolves as the latter.

[ussuri]

Sorry, I structured my comments in an unclear manner. Rephrasing:

• resolveToFullPath_('/', '.foo') would return '/foo' before - now returns '/.foo'
• resolveToFullPath_('/', 'a/b/../../foo') would return '/a/foo' before - now returns '/foo'
• resolveToFullPath_('/', 'a////b////foo') would return '/a//b//foo' before - now returns '/a/b/foo'

So, it seems you are in agreement with what this PR achieves :)

[ussuri]

I'll add a couple of comments in the code to explain why some of the above was happening.

[ussuri]

@ebidel: ping

[ebidel]

LGTM. Tests are passing :) Can you just address the one comment.

[ussuri]

Done!