Chaneg path scope & check excludedArray first

treePaths, diffPaths and deletedPaths now all namespaced to top level so
we can access from elsewhere
Check we have excludedArray first before looking at it's index. This is
to avoid issues when switching in and out of GitHub Diff mode.
Load screen, path removal, tweaks & error handling

Show loading screen on clicking Commit button
Committed filepaths need to have pipes replaced with slashes
Splice from diffPaths or deletedPaths array so we remove committed files
Hide Loading mask if we don't have more to commit
Only display alert message and toggle GitHub diff mode if we have no
diff or deleted paths left to deal with
Error message is an object, so inform user that we'll console.log that.
Path fixes for add and delete actions

When adding files, location should be a slash if not set
Remove any initial double slashes
When removing files, location should be blank if not set. Then replace
iceRoot with a slash, before reducing double slashes at start, slashes
for pipes and tack together with file to make the targetElem, which is
what we end up looking for
Update to match main JS file