new test: cc_lapack

- extended math_libs.cmake for C headers detection
- static_linking tests included
- rearranged math-libs order for better libraries detection
- no int64 for cc_lapack
- added include/ directory to %path% to detect clapack.h in appveyor
- simplified C-code, intendations kept
- travis-ci kept simple, but needs liblapack-dev and libatlas-base-dev
- libatlas-dev can not be installed due to repeating xerba objects in *.a lib
  files

.travis.yml

@@ -11,7 +11,8 @@ addons:
       - binutils-gold
       - libc6-dev
       - libpthread-stubs0-dev
-        # Math libraries
+        # Math libraries : SYSTEM_NATIVE-static/dynamic and ATLAS-dynamic only
+        # do not install libatlas-dev due to conflicts of repeating xerbla in *.a lib files
       - libblas-dev
       - liblapack-dev
       - libatlas-base-dev