Add a support of additional spaces inside TMPL_VAR construction.

Now this is valid:

<%TMPL_VAR  NAME=var%>
<%TMPL_VAR    DEFAULT=ee    NAME=var2%>
Add a support of additional spaces inside TMPL_LOOP construction.

Now this is valid:

<%TMPL_LOOP    NAME=loop1%>...<%/TMPL_LOOP%>
Add a support of additional spaces inside TMPL_IF/TMPL_UNLESS constructions.

Now this is valid:

<%TMPL_IF    NAME=var1%>...<%/TMPL_IF%>
<%TMPL_UNLESS   NAME=var2%>...<%/TMPL_UNLESS%>
Rename common functions.
Add hdlr_tag() to parse tag attributes.
Add a support of quoted attributes of tags.

It's implemented through phrases and may be it is ugly.