replaced code returning false and throwing logic_error into code to throw SQLProcessorException and AsuraException.
fixed the return type of SQLColumnParser::close() from bool to void. The error is now notified by an exception.
removed SQLFormulaParser::setError().

It is no longer needed, becuase the past fixes have replaced
returning errors into throwing exceptions.
changed the return type of SQLFormulaParser::*KeywordHandler.

Return type: bool -> void

The past fixes have replaced returning false into throwing
an exception. So now no need to return a result.
changed the return type of a function pointer.

Target    : SQLFormulaParser::*FunctionParser.
eturn type: bool -> void

The past fixes have replaced returning false into throwing
an exception. So now no need to return a result.
changed the return type of functions.

Changed functions:
- SQLFormulaParser::add()
- SQLColumnParser::add()
- SQLWhereParser::add()

Return type: bool -> void

The past fixes have replaced returning false into throwing
an exception. So now no need to return a result.
added a new stub function.

Added function: SQLProcesssorSelect::makeGroups()
Purpose:
- makes ItemTableGroupList when the statement has GROUP BY.
added a new stub function.

Added function:
- SQLProcesssorSelect::makeGroupedTable()

Purpose:
- makes a grouped ItemTable for the given column.
added a new function.

Added function:
- SQLProcesssorSelect::makeTextOutputForAllGroups()

Purpose:
- call makeTextOutput() for the all tables in grupedTables.
  This is added to perform GROUP BY.
implemented SQLProcessorSelect::makeGroupedTableForColumn().
implemented SQLProcessorSelect::makeGroupedTableForColumn() and SQLProcessorSelect::makeGroupedTable().
fixed the bug whose expected number of the selected rows is wrong.
fixed the bug that shows all rows even when 'group by' is specified.
moved the clear point of groupedTableMap to PrivateContext::clear() where other members are also cleared.
added a new test.

Test case name: test_innerJoinWithTableNames
cleaned up test_innerJoin().

used assertInnerJoinHeler() that is created in the previous commit.
deleted a variable that is not used.
fixed the bug that gives a table name as a column name.
supported inner join with a table variable.

Now, for instance, the following statment can be processed.
'select * from table1 a inner join table2 b on a.column1=b.column2'
fixed the wrong indent.