Non-linearly Spaced Vector Generator

nonLinspace(mn, mx, num, spacetype) returns a vector of non-linearly
spaced elements based on spacing specified by spacetype. This function
was made in order to provide domains for relationships or functions
which require greater resolution in some portions of the domain than
others.
An example would be the vortex panel method for determining pressure
distribution over an airfoil. Since the leading and trailing edges of the
airfoil see greater pressure gradients, more resolution is required in
these places as opposed to the middle of the airfoil, so cosine spacing
would be optimal for for determining panel boundary point distribution.
nonLinVec = nonLinspace(mn, mx, num, 'exp10') returns a vector of
elements with smaller spacing at the beginning of the vector and greater
spacing at the end of the vector based on the curve y = 10^x.

nonLinVec = nonLinspace(mn, mx, num, 'cos') returns a vector of elements
with smaller spacing at the beginning and end of the vector, and greater
spacing in the middle based on the curve y = 1/2(1-cos(x)).

nonLinVec = nonLinspace(mn, mx, num, 'log10') returns a vector of
elements with greater spacing at the beginning of the vector and smaller
spacing at the end of the vector.

Inputs:
mn - The minimum value in the vector.
mx - The maximum value in the vector.
num - The number of elements in the vector.
spacetype - Specifies the type of spacing needed.

Outputs:
nonLinVec - A vector consisting of elements with spacing specified
by spacetype.

Created: 10/12/17 - Connor Ott
Last Modified: 10/23/17 - Connor Ott