Release v0.5.0 on 2019-08-07.

1. ce5b996 import TR 25.931 with examples of signalling procedures by Harald Welte · 8 years ago
2. e98dacd add TS 25.412 spec by Harald Welte · 9 years ago
3. 9614d9a add more relevant/related specs by Harald Welte · 9 years ago
4. 243b00b add various management / OML related specs (32.57x, 32.58x, 32.82x) by Harald Welte · 9 years ago
5. 4bc90aa Add Specs in DOC format, not just PDF by Harald Welte · 9 years ago