Updates to FreqArray

[1oly]

Updated with arithmetic functions * and /

[codecov]

Codecov Report

Merging #4 (1728b8e) into master (e834c50) will increase coverage by 0.02%.
The diff coverage is 61.53%.

@@            Coverage Diff             @@
##           master       #4      +/-   ##
==========================================
+ Coverage   74.01%   74.04%   +0.02%     
==========================================
  Files          11       11              
  Lines         408      420      +12     
==========================================
+ Hits          302      311       +9     
- Misses        106      109       +3     

Impacted Files	Coverage Δ
src/AeroAcoustics.jl	70.96% <ø> (ø)
src/types.jl	72.22% <61.53%> (+5.55%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e834c50...1728b8e. Read the comment docs.