Added the files necessary to build EpyMC on Arch Linux

File: PKGBUILD
Reason: Required by makepkg to install the software

File: epymc.install
Reason: Needed to print the message out after the install containing the
instructions for compiling and installing the themes
Added .gitignore to ignore files created by makepkg
Updated README.md

Filename: README.md
Reason: Added a disclaimer regarding the LICENSE file stating that the
LICENSE only applies to the PKGBUILD and epymc.install file