A first stab at lesser blocks.

src/parser/greater_block.rs

@@ -37,7 +37,6 @@ pub fn greater_block<'r, 's>(
     // TODO: Do I need to differentiate between different greater block types.
     start_of_line(context, input)?;
     let (remaining, _leading_whitespace) = space0(input)?;
-    // TODO: Not handling indentation before start of block
     let (remaining, (_begin, name)) = tuple((
         tag_no_case("#+begin_"),
         verify(name, |name: &str| match name.to_lowercase().as_str() {