Fix URL query encoding (#78)

* Fix typos

* Fix encoding spaces in issuer name

Update travis for Go 1.15 (#58)

Merge pull request #42 from pquerna/pq/expose_setting_secret

Allow calls to {htop,totp}.Generate() to specify the secret

Merge pull request #31 from champkeh/hotp-digits-check

check hotp key generation opts.Digits

Merge pull request #19 from pquerna/pq/update_golang_versions

[CI] Update Golang versions on Travis