plugins: extracted Graph class

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
misc: renamed misc-memory.h to memory.h

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
misc: added algorithm file

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
misc: add graph_find_cycles alghoritm

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
misc: add graph_sort_successors alghoritm

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugins: return proper types from dependency graph objects

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>
plugins: implemented findDependencies with generic method

Signed-off-by: Rafał Malinowski <rafal.przemyslaw.malinowski@gmail.com>