Changeset 1033:9a51db038228 in lemon-main for doc

Document and greatly improve TSP algorithms (#386)

• Add LEMON headers.
• Add Doxygen doc for all classes and their members.
• Clarify and unify the public API of the algorithms.
• Various small improvements in the implementations to make them clearer and faster.
• Avoid using adaptors in ChristofidesTsp?.