Add get_copy method to NonZero/Odd

[tarcieri]

By adding a T: Copy bound, we can have a function equivalent to get which is const fn, since Copy types are !Drop and otherwise get needs to worry about destructors

[codecov]

Codecov Report

❌ Patch coverage is 0% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.81%. Comparing base (30626b4) to head (2fe368c).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/non_zero.rs	0.00%	5 Missing ⚠️
src/odd.rs	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1072      +/-   ##
==========================================
- Coverage   78.85%   78.81%   -0.05%     
==========================================
  Files         173      173              
  Lines       17725    17735      +10     
==========================================
  Hits        13977    13977              
- Misses       3748     3758      +10     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.