Add regression script

And make the current plot a global variable.
Now it is possible to get data from a plot,
perform the regression and then plot the data and result.
add new setting Fit to plot settings. In order to place html select menu besides its name, update the width of the three colums to allow for the extra space needed
remove all separate plot instances from all individual plot type selection and use only one function call after all if statements. Set only the data to be used in the if statements. And set variable to fit selection, in order to start using regression script. And add none value to fit selection if no fit is wanted
update comment to better reflect structure of multidimensional arrays
Make distiction between single- and multidimensional array when fitting
if input is disabled set text color to nearly invisible to avoid confusion
If from plot_type histogram is not selected disable bins from beïng edited. Add bin to choose degree when choosing polynomial fit
add Degree field for user to specify which degree the polynomial should have
Set polynomial degree input to disabled at first

Fixes #18
Number instead of text input for bins and degree

This allows easy way to 'limit' the input.
It is still possible to set value beyond the min/max,
but at least it will be discouraged.
Fixes #19
Use <br> instead of <br />
Merge branch 'master' into fitting
Axis label on canvas default

Fixes label for x-axis in time series
Degrees as symbol for wind direction units
Add variable summary to be able to eventually print the string which holds the fit formula
add toExponential method to rounding in return string to enhance the formula
use regex to put linear fit in Tex for proper Mathjax rendering
-Add mathJax\n-remove unnecessary variables\n-add Tex formulas for linear fit\n- unhide/hide div\n\n-Still need to remove previous formula if new fit is selected
-Add mathJax
-Remove unnecessary variables
-Add Tex formulas for linear fit
-Unhide/hide results div

-Still need to remove previous formulas if new fit is selected
-Add Tex formulas for all fits
Merge branch 'fitting' of https://github.com/HiSPARC/jsparc into fitting
Improve axis labels and variable list

Specified the variable names explicitly in the formats.
These have proper capitalization.
Also used for the axis labels, which now includes units.