Add some testing for fallback, some testing that media-level-only
atrtibutes in the session level are properly ignored (both during
parse, and by HasAttribute). Fixing bugs uncovered by these tests.
Merge pull request #116 from nils-ohlmeier/multistream

More SCTP improvements
Merge pull request #117 from docfaraday/multistream_unit_tests

Add some testing for fallback, some testing that media-level-only
Fix a pedantic compiler error.
Fix another pedantic compiler error, and make a test-case fixtureless
since it didn't use the fixture.
Merge pull request #119 from docfaraday/multistream_unit_tests

Multistream unit tests
fixed sctpmap memory leak (issue #118)