Add UT to validate that the data is set correctly on the sub class of Schema
space instead of tab
fix the class redefine error in sub class of Schema
1. change class Table_Stats to Table_Stats_$type
2. change class Relation_Stats to Relation_Stats_$type
split output from constructor for Schema classes
remove "exit" which is unneeded action
Merge pull request #490 from adamgsoc2013/UT_plu_schame

Add UT to validate that the data is set correctly on the sub class of Schema