added input validation and sanitizing for mitigating RCE vulnerabilities
added XSS protection to submitted URLs
changed serval-{sign,verify} calls to match new serval-crypto format
fixed url encoding error
Merge pull request #21 from opentechinstitute/fix-RCE

Added input validation and sanitizing for mitigating RCE vulnerabilities. Successfully tested by @jheretic.
Merge pull request #24 from opentechinstitute/serval-crypto

changed serval-{sign,verify} calls to match new serval-crypto format
fixed some merge errors