adw 0.2.1

• fix the BugReports website.
• add README file

adw 0.2.0

• all of the functions of sf package were replaced by the functions of terra package. The calculation speed will be several times faster than before.
• add parameters of extent, nmin, nmax, and maskON
• parameter gridSize were changed to gridsize
• delete parameters of xmin, xmax, ymin, ymax
• delete adw_land function. The new version of the function ‘adw’ adds a parameter ‘maskON’ to implement the function of the mask.