[FIX] Using module random in readSimulator.h
[FIX] Applying umask() before mkstemp to silence Coverity warning.
[FIX] Using std::string as a buffer in test_graph_tcoffee.h.
[FIX] Using module random instead of random().
[FIX] Using umask in mason2.
[FIX] Using module random in test_index_creation.h.
[FIX] Using std::string as a buffer in test_statistics_base.h.
Merge pull request #633 from holtgrewe/feature/small-improvements

Various small improvements and fixes.