Fix malloc error 'Incorrect checksum for freed object' for custom spacing functions

[n-claes]

PR description

It seems that #129 introduced a pesky bug if the dx spacing function was chosen in such a way that the number of gridpoints increased with respect to the user-set gridpoints, such that these got updated. This change was not propagated correctly to the eigenvalue/eigenvector arrays, which were initialised too early.
This led to the following error, which popped up at completely random times

legolas(32399,0x7ff85dcc8340) malloc: 
Incorrect checksum for freed object 0x7f9cb4012400: probably modified after being freed.
Corrupt value: 0x3ff1e376c990c00a
legolas(32399,0x7ff85dcc8340) malloc: *** set a breakpoint in malloc_error_break to debug

Program received signal SIGABRT: Process abort signal.
zsh: abort      ./legolas -i config.par

Re-arranging array allocations in the main program so they take place after the grid has been initialised (and thus use the modified number of gridpoints) seems to have fixed the issue.

Bugfixes

Legolas

• Heisenbugfix: malloc error at random intervals when specifying a custom spacing function

[codecov]

Codecov Report

Merging #135 (04feed7) into develop (b255f61) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #135   +/-   ##
========================================
  Coverage    90.64%   90.65%           
========================================
  Files          158      158           
  Lines         8893     8899    +6     
========================================
+ Hits          8061     8067    +6     
  Misses         832      832           

Flag	Coverage Δ
legolas	93.14% <100.00%> (+<0.01%)	⬆️
pylbo	86.13% <ø> (ø)

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