fix a bug when using grouping sets without all column in a grouping set item will produce wrong value.
fix grouping function check will not work in group by clause
Support Grouping Sets, Rollup and Cube to extend group by statement
support GROUPING SETS syntax
```
SELECT a, b, SUM( c ) FROM tab1 GROUP BY GROUPING SETS ( (a, b), (a), (b), ( ) );
```
cube or rollup like
```
SELECT a, b,c, SUM( d ) FROM tab1 GROUP BY ROLLUP|CUBE(a,b,c)
```
[ADD] support grouping functions in expr like grouping(a) + grouping(b) (#2039)
[FIX] fix analyzer error in window function(#2039)
Leverage gitattributes to enable auto convert end-of-line to LF when
checking in. Convert already exist CRLF to LF by removing all files and
checking out with new .gitattributes file. Except .gitattributes, all
files are only modified at the end of line.
