Reworking of lapack_shared_libs and similar properties (#1682)

* Turned <provider>_libs into an iterable

Modifications :
- added class LibraryList + unit tests
- added convenience functions `find_libraries` and `dedupe`
- modifed non Intel blas/lapack providers
- modified packages using blas_shared_libs and similar functions

* atlas : added pthread variant

* intel packages : added lapack_libs and blas_libs

* find_library_path : removed unused function

* PR review : fixed last issues

* LibraryList : added test on __add__ return type

* LibraryList : added __radd__ fixed unit tests

fix : failing unit tests due to missing `self`

* cp2k and dependecies : fixed blas-lapack related statements in package.py

var/spack/repos/builtin/packages/hypre/package.py

@@ -60,13 +60,14 @@ def install(self, spec, prefix):
         # to command the linker to include whole static libs' content into the
         # shared lib
         # Note: --with-(lapack|blas)_libs= needs space separated list of names
+        lapack = spec['lapack'].lapack_libs
+        blas = spec['blas'].blas_libs
+
         configure_args = [
             '--prefix=%s' % prefix,
-            '--with-lapack-libs=%s' % to_lib_name(
-                spec['lapack'].lapack_shared_lib),
+            '--with-lapack-libs=%s' % lapack.names,
             '--with-lapack-lib-dirs=%s' % spec['lapack'].prefix.lib,
-            '--with-blas-libs=%s' % to_lib_name(
-                spec['blas'].blas_shared_lib),
+            '--with-blas-libs=%s' % blas.names,
             '--with-blas-lib-dirs=%s' % spec['blas'].prefix.lib
         ]