#4 Patch for some compilation errors

[Nicola Soranzo]

In the attached patch, there are fixes for the following compilation errors:

• missing include in show-diff.cc
• unneeded use of -static and of -lbgl-viz -lboost_graph-gcc41-mt when linking in chaining/Makefile
• fix for Boost >= 1.42.0 in chaining/synchain-mugsy.cpp
• fix for Boost >= 1.47.0 in chaining/synchain-mugsy.cpp and mugsy-seqan/projects/library/apps/mugsy/mugsy.cpp

I hope you can apply all of them!

[Nicola Soranzo]

I'm attaching a better patch which should work for both old and new versions of Boost.