Changing behavior of "m_Comments" tag to better support internal comments

Currently <inp2: tags inside HTML comment tags are not processed, but there are cases, like:

<!--[if IE 6]><script type="text/javascript"
src="<inp2:m_TemplatesBase/>/js/min-max.js"></script><![endif]-->

when they should work. Currently we have tag <inp2:m_Comment>...</inp2:m_Comment> that doesn't show it's contents after parsing. It's pretty useless since we can write comments in form <!--# to
remove ##--> that will do the same without additional tags. I propose we
make <inp2:m_Comment> tag create areas in template where <inp2: tags inside
comments could be parsed (it will change NParser->InsideComment mark and
then restore it's back at the end). Resulting code will be:

<inp2:m_Comment><!--[if IE 6]><script type="text/javascript"
src="<inp2:m_TemplatesBase/>/js/min-max.js"></script><![endif]--></inp2:m_Comment>

We could also rename this tag to make sure it's named by the action it does.