db:mysqldb: introduce two new methods.

1) ifTableExist() returns if a table does exist.
2) createTableTemplate() creates a table using templates.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
dataMgr: introduce data manager subsystem.

Add two importers.
1) importer.py contains 'Import' class which is proposed to be the
   super class for all child Importers.
2) Introduce whImporter to support WenHua format data records.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
test: add test for dataMgr/importers.

Add test because introduced new dataMgr subsystem.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>