store file properties separated from value of file field

Many minor cleanups and PHPDocs
Perform replacements in To-addresses of mail action. Fixes #101
allow also default options of empty string in field parser regexp

Fixes #98

for the syntax
select Fruit "|Peaches|Apples|Oranges"
The default select value is the first entry (an empty string),which is
not recognized by the _parse_tpl() because the regexp did not allow
@@Apple|@@. Regexp allows now zero characters after the | .
Set initial state of yesno with ==1 or ==0 Fixes #97
Improve floating submits and tight placing of fields. Fixes #95
Added required="required" to text inputs and textarea. Fixes #94
datepicker selector more specific. Fixes #91
Each form its own captcha. Fixes #6

- Finetune spacing between forms.
Merge pull request #108 from splitbrain/branch

Branch