GenerateInitialPop: Generate an Initial Population
In npollesch/FishToxTranslator: The Fish Toxicity Translator

This creates an initial size distribution for indiviudals using either a uniform, random uniform, or random normal distribution

1	GenerateInitialPop(mpts, z_hatch, z_inf, n_0, init_dist = "unif")

`mpts`	Midpoints of the discretized kernel that the size distribution is being generated for [vector]
`z_hatch`	Minimum size of individuals [float]
`z_inf`	Maximum size of individuals [float]
`n_0`	Number of individuals to initialize population with [integer]
`init_dist`	The initial distribution to follow, three options 'Uniform', 'Random Uniform', 'Normal' Uniform : Exactly uniformly distributed among all size classes Random Uniform: Randomly uniformly distributed ~U[z_min,z_max] Normal: Truncated normal distribution between 'z_min' and 'z_max' with mean = 'z_min'+'z_max'/2 and sd=1