Get the word under the cursor returning the start and end positions.

def word_at_position(self, position):
        """Get the word under the cursor returning the start and end positions."""
        if position['line'] >= len(self.lines):
            return ''

        line = self.lines[position['line']]
        i = position['character']
        # Split word in two
        start = line[:i]
        end = line[i:]

        # Take end of start and start of end to find word
        # These are guaranteed to match, even if they match the empty string
        m_start = RE_START_WORD.findall(start)
        m_end = RE_END_WORD.findall(end)

        return m_start[0] + m_end[-1]