Support single line compound statements

For single-line compound statements, "end" should be put at the end of the line:

``` python
if a > 28: a = 3; end
```

In order to parse this correctly, we need more info from lexical analysis. Note that checking lineno is not enough to tell if it is a single-line statement due to logical lines. For example:

``` python
if a > 28: \
      a = 3; end
```
