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 Integration functions
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Functions are available in integration.jl to be able to integrate the area under a region of a spectrum, or to integrate the area under Gaussian, Lorentzian or other peaks built from the functions provided in functions.jl.

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 Function trapz
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At the moment, only two functions are available. trapz is an implementation in Julia of the trapezoïdal integration function available in Matlab for instance. Call it as:

    area = trapz(x, y)

INPUTS:

	x: Vector{Float64} containing the x values;
	
	y: Vector{Float64} containing the y values;

OUTPUTS: 

	area: Float64, the trapezoidal integration value

This function is particularly helpful to calculate the area under a portion of a spectrum, and can be used for various purposes (normalisation, area comparison, etc.).

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 Function gaussianarea
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gaussianarea allows to calculate the area under a gaussian peak from its half-width at half maximum (hwhm) and its amplitude, with the possibility of calculating the error based on the inputs of the errors on hwhm and amplitude. Call it as:

    area, esearea = gaussianarea(Amplitude,HWHM; eseAmplitude = [0.0], eseHWHM = [0.0])

INPUTS:

	Amplitude: Array{Float64} containing the amplitudes

	HWHM: Array{Float64} containing the half width at half maximum of the peaks

	eseAmplitude: Array{Float64} containing the errors affecting Amplitude

	eseHWHM: Array{Float64} containing the errors affecting HWHM

OUTPUTS: 

	area: Array{Float64} contaning the areas

	esearea: Array{Float64} contaning the propagated errors affecting the areas calculations. If eseAmplitude and eseHWHM are not indicated, the function will return 0.0 for esearea, the error made on the area calculation.