Updated some typos

Fixed some incorrect variable references.
Makes the error names consistent
Don't refer to flaskext in docs
Merge pull request #886 from talam/patch-1

Updated some typos
Merge pull request #890 from seancron/documentation-fix

Documentation fix: Makes the error names consistent
Merge pull request #891 from ThiefMaster/docs-flaskext

Don't refer to flaskext in app.extensions docs
Clear exceptions when pushing a context

Fixes #882
Merge branch '0.10-maintenance'
Fix typo s/at at/at a/
Fix typo in docs for error_handler_spec
Merge pull request #895 from daybarr/patch-1

Fix typo in docs for error_handler_spec
fix typo
Merge pull request #899 from pengfei-xue/master

fix typo(there-> their)
Changed the wording of some sentences there were difficult to understand.
Rewrapped lines
Happy New Year 2014
Merge branch '0.10-maintenance'
Added a favicon for the docs
Merge pull request #943 from skeuomorf/favicon

Added a favicon for the docs
Release as universal python wheel (2/3 compat)