Fix sum of Grads

[pvillacorta]

This is a temporary change to solve a bug when rotating sequences:

julia> using KomaMRI
julia> seq = PulseDesigner.EPI_example()
julia> plot_seq(seq[1:10])

julia> seq_r = rotz(π/2) * seq
julia> plot_seq(seq_r[1:10])

This bug happens when rotating a Sequence, as we are implicitly calling +(Grad(0, 0), Grad(A, T)), and this function assigns the T, delay, rise and fall of the first Grad to the result. A temporary solution is to assign the maximum of each one of these values:

+(x::Grad, y::Grad) = Grad(x.A .+ y.A, max(x.T, y.T), max(x.rise, y.rise), max(x.fall, y.fall), max(x.delay, y.delay)) 

But a better solution would be to "stack" the gradients if they have different time-related parameters. See #487

[github-actions]

KomaMRI Benchmarks

Benchmark suite	Current: 13c690c	Previous: 5df34cb	Ratio
MRI Lab/Bloch/CPU/2 thread(s)	238195724.5 ns	223767376.5 ns	1.06
MRI Lab/Bloch/CPU/4 thread(s)	169331898 ns	130477217 ns	1.30
MRI Lab/Bloch/CPU/8 thread(s)	86911436 ns	138275342 ns	0.63
MRI Lab/Bloch/CPU/1 thread(s)	347229312 ns	347398917 ns	1.00
MRI Lab/Bloch/GPU/CUDA	55542254.5 ns	56227105 ns	0.99
MRI Lab/Bloch/GPU/oneAPI	500467925 ns	496678721 ns	1.01
MRI Lab/Bloch/GPU/Metal	551118604 ns	559269812.5 ns	0.99
MRI Lab/Bloch/GPU/AMDGPU	34655907 ns	34678068 ns	1.00
Slice Selection 3D/Bloch/CPU/2 thread(s)	1004510044 ns	1144007818 ns	0.88
Slice Selection 3D/Bloch/CPU/4 thread(s)	572369922 ns	609258944.5 ns	0.94
Slice Selection 3D/Bloch/CPU/8 thread(s)	337693200 ns	378398584 ns	0.89
Slice Selection 3D/Bloch/CPU/1 thread(s)	1950723198 ns	1928663456 ns	1.01
Slice Selection 3D/Bloch/GPU/CUDA	101462465 ns	101329308.5 ns	1.00
Slice Selection 3D/Bloch/GPU/oneAPI	635759355 ns	635643734 ns	1.00
Slice Selection 3D/Bloch/GPU/Metal	553018250 ns	554670167 ns	1.00
Slice Selection 3D/Bloch/GPU/AMDGPU	58719048 ns	58892774 ns	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.27%. Comparing base (386cf0d) to head (e03607a).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #486   +/-   ##
=======================================
  Coverage   90.27%   90.27%           
=======================================
  Files          54       54           
  Lines        3055     3055           
=======================================
  Hits         2758     2758           
  Misses        297      297           

Flag	Coverage Δ
base	86.24% <100.00%> (ø)
core	93.13% <ø> (ø)
files	91.69% <ø> (ø)
komamri	93.98% <ø> (ø)
plots	91.32% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
KomaMRIBase/src/datatypes/sequence/Grad.jl	87.87% <100.00%> (ø)

[cncastillo]

Looks good to me, thanks!