First implementation of test classes and their integration into the Makefile.

. new file:   include/blocking_queue_test.cpp
  . First set of test cases.

. deleted:    test/.gitinclude
  . Decided that I would keep the test classes directly alongside the source
    so no need for this directory.

. modified:   Makefile
  . Added additional targets to be able to compile the test classes along
    with the rest of the source and a target to run the tests.
  . Reformatted the file (spacing)
  . Added a BLOCKING_QUEUE_TEST_TARGET and BLOCKING_QUEUE_TEST_TARGET_OBJS
    macro definition.
  . Updated the clean: target to output info to the shell.
  . Implemented additional targets to compile and link the first test
    class (blocking_queue_test.cpp)
  . Added a test: target to run the tests.

. modified:   bin/.gitignore
  . Ignore everything in this dir.

. modified:   include/blocking_queue.hpp
  . Added additional function to facilitate testing:
    . size_t get_size()
  . Added doxygen comments.