Add functions for tox crate version information

[antis81]

Adds functions to query and display the tox crate version during runtime.

• tox::tox_node::crate_version -> String
• tox::tox_node::crate_version_major -> u32
• tox::tox_node::crate_version_minor -> u32
• tox::tox_node::crate_version_patch -> u32

[kpp]

Would you please explain what you are fixing by this PR? Can you add more context? Error messages?

[antis81]

Actually this feature is available in c-toxcore (for example here). The PR adds those API calls to the "tox" crate. Might be better suited in both "tox" and "tox_core" crate though. This allows to query and display (meta) information about the tox(_core) crate at runtime.

[coveralls]

Pull Request Test Coverage Report for Build 7247588774

• 19 of 19 (100.0%) changed or added relevant lines in 1 file are covered.
• 13 unchanged lines in 7 files lost coverage.
• Overall coverage decreased (-0.03%) to 94.85%

---

Files with Coverage Reduction	New Missed Lines	%
tox_core/src/net_crypto/mod.rs	1	98.47%
tox_core/src/state_format/old.rs	1	85.11%
tox_packet/src/dht/errors.rs	1	75.0%
tox_core/src/onion/client/paths_pool.rs	2	85.47%
tox_packet/src/onion/mod.rs	2	93.62%
tox_core/src/relay/links.rs	3	98.3%
tox_node/src/node_config.rs	3	72.92%

Totals
Change from base Build 5022320978:	-0.03%
Covered Lines:	16816
Relevant Lines:	17729

---

💛 - Coveralls

[kpp]

Ok good. Can you integrate these functions into Tox-node?

[antis81]

Okay I moved the version info into the tox_node crate together with the version context. Now we have a "human readable" form in addition to this somewhat "cryptic" versioning scheme. However for the time being I say it is fine.