Change alpha beta to theta delta

[1-Bart-1]

Closes #116

[codecov]

Codecov Report

Attention: Patch coverage is 58.62069% with 12 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/kite_geometry.jl	28.57%	5 Missing ⚠️
src/wing_geometry.jl	0.00%	5 Missing ⚠️
src/panel.jl	77.77%	2 Missing ⚠️

Files with missing lines	Coverage Δ
src/VortexStepMethod.jl	2.63% <ø> (ø)
src/body_aerodynamics.jl	89.10% <100.00%> (ø)
src/plotting.jl	91.21% <100.00%> (ø)
src/panel.jl	72.04% <77.77%> (ø)
src/kite_geometry.jl	81.99% <28.57%> (ø)
src/wing_geometry.jl	80.68% <0.00%> (ø)

🚀 New features to boost your workflow:

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