Von mises range fix

[Astro-mh]

This pull request reverts part of #965 which added bound checking to the pdf of several distributions. This shouldn't be done for the von Mises distribution as it is designed to be periodic, repeating every 2π, so values for the pdf beyond the support of the distribution are entirely valid.

To enable the univariate_bounds tests to continue working with as few changes as possible, this also adds an isperiodic() method which is set to false in univariates.jl and then set to true in vonmises.jl

[codecov-io]

Codecov Report

Merging #1280 (e492112) into master (0b1ecad) will decrease coverage by 1.96%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1280      +/-   ##
==========================================
- Coverage   81.34%   79.38%   -1.97%     
==========================================
  Files         117      117              
  Lines        6563     5977     -586     
==========================================
- Hits         5339     4745     -594     
- Misses       1224     1232       +8     

Impacted Files	Coverage Δ
src/Distributions.jl	100.00% <ø> (ø)
src/univariate/continuous/vonmises.jl	84.37% <100.00%> (-3.51%)	:arrow_down:
src/univariates.jl	65.97% <100.00%> (-0.70%)	:arrow_down:
src/univariate/discrete/hypergeometric.jl	56.75% <0.00%> (-6.66%)	:arrow_down:
src/univariate/discrete/skellam.jl	75.00% <0.00%> (-6.25%)	:arrow_down:
src/univariate/continuous/normalinversegaussian.jl	79.16% <0.00%> (-6.02%)	:arrow_down:
src/univariate/continuous/skewnormal.jl	61.29% <0.00%> (-4.34%)	:arrow_down:
src/univariate/continuous/biweight.jl	56.66% <0.00%> (-3.94%)	:arrow_down:
src/matrix/wishart.jl	84.04% <0.00%> (-3.81%)	:arrow_down:
... and 94 more

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[jerlich]

It is frustrating that this PR (and other PR) related to VonMises are not resolved and merged. The current implementation gives unexpected results.

It seems that the simplest solution to these issues is to define support on [-pi , pi] and then wrap input (to pdf or cdf) to this range and likewise, always give samples in this range.

[devmotion]

I reviewed the PR and it seems the PR is clearly not in a mergeable state. The comments have to be addressed first but apparently this has not been done.