Proofreading or reqcontext.rst
Proofreading of reqcontext.rst, shell.rst and security.rst
Merge branch 'master' of https://github.com/yinian1992/flask-docs-cn
Proofreading of signals.rst and add new content
Proofreading of styleguide.rst
typo
Merge pull request #10 from atupal/master

Proofreading : reqcontext.rst, security.rst shell.rst signals.rst styleguide.rst