Merge pull request #2 from MikaelSmith/fix-tests-boost-dependency

Fix Windows tests and add Boost dependency
initial appveyor ci build commit
add os:unstable for x64 boost builds
fix appveyor's boost compiled binaries paths
fix git clone twice, fix boost binaries path for x86 builds
specify absolute path to compiled project
try to build solution before run testing
try to build solution before run testing #2
try to build solution before run testing #3
try to build solution before run testing #4
try to use script mode to build and test
trying fix appveyor build #5
trying fix appveyor build #6
trying fix appveyor build #7
trying to run tests after build
add appveyor build status badge
clean unnecessary directory lookup
Enhance test paths

If the test paths are changed by an including project, for example via
EXECUTABLE_OUTPUT_PATH, add_test with the explicit COMMAND option will
substitute the correct path for the specified executable.