Remove 'method' decorator-like beast.
Remove docs for 'method' and 'missing'.
Remove unused import.
Delete tutorial example for type-checked methods.
Remove one more doc reference to type-checked methods.
Remove C-level machinery for type-checked trait methods.
Remove some type-checked method support functions.
Remove one more doc reference.
Merge remote-tracking branch 'origin/master' into fix-madness-in-method
More doc fixes.
Merge remote-tracking branch 'origin/master' into fix-madness-in-method

Conflicts:
	traits/api.py
	traits/ctraits.c
	traits/has_traits.py
BUG: Clear the exception when raising a TraitError.

When we call raise_trait_error(), we are usually doing so after some other
exception has been raised. In Python code, we would be catching this error
using `try: except: raise TraitError()`. In C, we use `PyErr_Clear();
raise_trait_error();`.
Merge pull request #119 from enthought/fix-clear-error

BUG: Clear the exception when raising a TraitError.
Merge pull request #112 from enthought/fix-madness-in-method

Fix madness in method.
Merge remote-tracking branch 'origin/master' into enh-run-tests-with-coverage