Log Message:
srtp: updated to 2.6.0

2.6.0

- remove use of pointers to 32bit values
- Cleaning up cmake and enabled more warnings.
- start using const on internal arguments
- Some srtp_driver fixes
- remove travis reference from README.md
- meson.build: implement mbedtls support
- iv length is constant so set only once
- Add x86 SIMD optimizations to crypto datatypes
- Add a missing typedef for stream list ctx
- cmake: Rename TEST_APPS as LIBSRTP_TEST_APPS option
- cmake: Support configuring as subproject