Parse decimal shorthand as number rather than string

[LukeTemp]

Issue: #33

Before:

>>> lua.decode("""{ SizeZ = .8, }""")
{'SizeZ': '.8'}
>>> lua.decode("""{ SizeZ = 0.8, }""")
{'SizeZ': 0.8}

After:

>>> lua.decode("{ num = .8, }")
{'num': 0.8}
>>> lua.decode("{ num = 0.8, }")
{'num': 0.8}