Merge pull request #67 from Sjlver/master

Fix wrong include guard.
Adding -Wheader-guard to CMakeLists.txt

Thanks to Sjlver for the idea. Related to issue #67
Fix PDF links
Merge pull request #69 from willglynn/patch-1

Fix PDF and bib links in README
Removed the disgusting MERGE_STATIC_LIBRARIES and all uses of it.

Now when libstp is built the boost-library will not be merged in to
it. CMake clients of libstp

* the stp executable
* Any CMake project that imports our targets

will automatically know which Boost libraries to link in.

Clients of libstp (e.g. KLEE )who do not use CMake will now have to link
in the right Boost libraries manually to their application
Merge pull request #70 from stp/remove_merge_static_libs

Removed the disgusting MERGE_STATIC_LIBRARIES and all uses of it.
Fix bashisms.

These were found by running checkbashisms on all shell scripts in the
project.