Exclude foundation.css wiredep if a CSS preprocessor is enabled

Close #166
Ensure module sorting, closes #162

Note, `{read: false}` needed to be omitted so that gulp-angular-filesort could
read each file's contents, see:
https://github.com/klei/gulp-angular-filesort/pull/14
Merge pull request #164 from tlvince/bug/module-sorting

Add gulp-angular-filesort to avoid nomod error
Add wiredep exclusions test checks
Merge pull request #167 from Toilal/foundation-wiredep-scss

Exclude foundation.css wiredep if a CSS preprocessor is enabled
Fix e2e tests #131.
Include e2e gulp test back into npm test.
Make main.po.js a template file. Refactor gulp e2e, remove gulp sync. Update related tests.
Recover package.json.
Remove gulp sync.