rapps: Add Ghostscript & GhostView

GhostScript & GhostView are tools for manipulating and viewing (Extended) PostScript files (.ps and .eps). They are usually used in conjuction with *TeX tools.

Since there are 2 licenses available for those tools, the Affero GNU GPL license and a comercial one, I propose only the AGPL one here:

• For Ghostscript, see: http://www.ghostscript.com/download/gsdnld.html and http://downloads.ghostscript.com/public/gs914w32.exe for the latest version up to now (9.14)
• For GhostView, see: http://pages.cs.wisc.edu/~ghost/gsview/get50.htm and http://pages.cs.wisc.edu/~ghost/gsview/download/gsv50w32.exe

(Some additional command-lines tools can be found here: http://pages.cs.wisc.edu/~ghost/gsview/epstool.htm )

Suggestion: Add it in the "Office" section of RApps.