Do not catch all exceptions on assert_invalid
Improve debug output of failed assertions
Add assert_syntax_invalid command
Use new syntax_invalid command in cql_tests
Assert unauthorized instead of invalid
Remove use of undeclared variable in assert_none
assert_invalid accepts expected Exception to be thrown
Merge branch 'master' into assertion-improvements

Conflicts:
	cql_tests.py
Merge pull request #114 from riptano/assertion-improvements

Assertion improvements