Remove xml2js dependency from contacts api

Jira issue: WP-670
Use the C14N_ALGORITHMS structure to determine if a transform is supported.

Jira issue: wp-528
Fix typo sigNum -> signum

Jira issue: wp-528
Merge pull request #396 from TobyEalden/wp-528-dig-sig-tests

fix dig sig tests
Merge pull request #389 from michelemorello/WP-670

Remove xml2js dependency from contacts api
Removed auto completion gmail.com suffix
Jira issue: WP-638
Merge pull request #397 from michelemorello/WP-638

Removed auto completion gmail.com suffix