Update fs_selfservice/FS-SelfService/cgi/signup.html

Fixed two instances where the following markup is being produced (lacking space before SELECTED): 

<OPTION VALUE=""SELECTED>
Update fs_selfservice/FS-SelfService/cgi/signup.html

Fixed typo.
Encode prepaid_shortform  input to prevent XSS
fix XSS
Merge branch 'xss_fixes' of https://github.com/mcreenan/Freeside
Merge branch 'patch-19' of https://github.com/gjones2/Freeside
Merge branch 'patch-18' of https://github.com/gjones2/Freeside