ChangeLog for PGPlot PKGBUILD

* pgplot-5.2.2-7 (2015-05-09 - AstroFloyd)
	Hijacked package from jmorin (last version is 3 years old)
	Split build in build() and package() (install) parts
	Link to X11 using the -lX11 flag
	Added ChangeLog

* pgplot-5.2.2-6 (2012-09-20 - jmorin)
	Last version from AUR3, hijacked by AstroFloyd for AUR4