src/template/: Make variables available via property of template class ($this->__vars) instead of simple local variable ($vars) so as to make the template variables available to sub-classes/sub-templates.
src/template/inheritance.php: Properly expand shorthand syntax within blocks; require blocks (at least for now) to begin and end in the first column of the file (i.e., the "block" keyword and the corresponding closing bracket *must* be at the very beginning of the line, without whitespace preceeding either).