change 'site' to 'blog'
update translation messages per Katina's revisions

Including:
 * "site-wide" regularized to "sitewide"
 * "email" standardized to "e-mail"
 * "username" standardized to "user name"
 * "full size" changed to "full-size"
'sitewide' -> 'site-wide'
blog -> site
username -> user name
changed 'edit my profile' and others, fixes #4