Change character sprites to match their actual roles

Change character sprites to match their actual roles

During development, characters got different roles than I initially
thought up. Character sprites are changed to reflect this.

Clara works at Reception instead of Accounting.
Peter works at Accounting instead of Design & Development.

Clara's and Saiki's colors are swapped (Clara got yellow and
Saiki got green), because Saiki works at the green department.

	modified:   clara.png
	modified:   clara.svg
	modified:   peter.png
	modified:   peter.svg
	modified:   saiki.png
	modified:   saiki.svg