Fully handle the symbol specification
Treat nil as a special symbol, rather than its own thing.
Merge branch 'master' into short-symbols

Conflicts:
	edn/tests/test_ast.py
Merge branch 'master' into nil-again

Conflicts:
	edn/tests/test_extended.py
Reorder rule rather than making exceptions
Merge pull request #18 from jml/nil-again

Fix nil, true & false parsing
Merge pull request #15 from jml/short-symbols

Fully handle the symbol specification
Merge branch 'master' into streaming