Version 0.5.3

• Fixes bug in ssg_group_refresh
• Uses margo logging functionalities instead of fprintf

v0.5.2

• fix potential deadlock on finalize()
• fix memory leak on refresh()

v0.5.1

• fix version number propagation to pkgconfig file
• address sanitizer fixes
• expanded init() path unit tests
• fix for dangling state after ssg_init() failure