[TYPO3-project-seminars] Make seminars onetimeaccount output valid XHTML

[Frederik Fischbach]

Hi there!

I encountered, that seminars and onetimeaccount don't output valid XHTML.

For example, on onetimeaccount registration and during booking process 
in seminars, I find something like this:

<select name="tx_seminars_pi1_registration_editor[price]" 
id="tx_seminars_pi1_registration_editor[price]"     >

w3c.org HTML Validator complains about charakters like "[" and "]", 
which violate naming conventions. "[" and "]" must not be used in the 
values of attributes "for" and "id" (this applies to "class", too, 
probably; I'm not sure about "name").

Moreover (I found this on onetimeaccount page and during booking process 
steps) sometimes "&" is not encoded with it's corresponding entity "&amp;".
Besides <textarea> requires attributes "rows" and "cols".

Are these problems real bugs or did I misconfigure anything?

I've set config.xhtml_cleaning = all in my TS.

Regards,
Fred