add pumpkinexception，debug，fix bug unescape.
fix redirect
little fix test app.py
add a orm framework.
init orm test.
Update README.rst
add many to many， make metaclass BaseModel compatible with python 3
add basic sql query functions
orderby，like
many to many field: append, remove, count, all and some little fix.
update test prototype.
fix metaclass compatibility between py2 and py3
想想测试也是醉了
add *.db in gitignore
Merge branch 'master' of https://github.com/jasonlvhit/pumpkin