rapps: Add MikTeX 2.9

MikTeX is THE LaTeX distribution for Windows-like environements. Since I want it to be added to rapps, I give a link to its web-installer (further details here: http://miktex.org/download ) : http://mirrors.ctan.org/systems/win32/miktex/setup/setup-2.9.4503.exe
Size: 7.01 MB
This distribution has a package manager that lets the user to download whichever latex package he wants, and even to download packages on the fly when he compiles his document.

Note: The provided GUI editor (called TexWorks) is a Qt app, so it inherits of all the problems of Qt apps in ReactOS atm. However it works more or less correctly for common usage.

Suggestion: Add it in the "Office" and "Science" sections of RApps.