A bare minimal Makefile project

Consist of:
1. Root level Makefile
2. src level Makefile
3. header and source files in src
4. .gitignore to ignore compile results
Added Travis CI configuration
Added a test that make sense

Assert the expected result of hello library
Finish the basic feature

Finish the feature that fulfills the unit test
Added test and declaration of "foo"

Declared and test the new foo function
Finished foo as specified
Changed to build library archive file

Build archive file (lib/libhello.a) with the objects.
Also changed the unit test to build against the archive file.
Use LD_LIBRARY_PATH in test building

Prepare for dynamic library build
Build as dynamic library