refs #5, refs #8

added validation and warnings on piwik host, site id and auth token in
module admin refs #8
added more currency stuff #5
moved some code around
added function to get site in piwik using piwik api
added Referral Cookie Timeout

moved all session/cookie timeouts to adv section
now all session/cookie timeout values must be set in minutes
added so they are only added to template if not piwik defaults
fix setCookieDomain and setDomains

fix setCookieDomain so an empty value equals excluding it from the
tracking code
fix setDomains to allow empty "excluding it from the tracking code" and
to allow multiple domains separated by space (array of domains)
closes #8

added warnings and excluding tracking code from being added to website
if configuration is wrong