#163 Smiles parser fails on many fragment string

[Egon Willighagen]

Smiles parser fails on
"C.C.N.C.C.C.[H].[H].[H].[H].[H].C.C.[H].[H].[H].[H].[H]".
Clearly, this is not what was meant, but
nevertheless, a valid SMILES tring. The error that
occurs:
org.openscience.cdk.exception.InvalidSmilesException:
Expected element symbol, found null!
junit.framework.AssertionFailedError:
org.openscience.cdk.exception.InvalidSmilesException:
Expected element symbol, found null!
at
org.openscience.cdk.test.smiles.SmilesParserTest.testSMILESFromXYZ(SmilesParserTest.java:490)
at
sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

A JUnit test has been added to
test.tools.SmilesParserTest.