fAddSiteMeta2Plot: Add site metadata to ggplot
In ksmiff33/FluxSynthU: Suite of functions to analyze eddy covariance data

Takes an existing ggplot object and adds site metadata as a title

1	fAddSiteMeta2Plot(plot, site, db, longname, country, lat, long, MAT, MAP, IGBP)

`plot`	a ggplot object.
`site`	6-character site code (e.g. 'US-NR1').
`db`	3-character database code (e.g. 'FLX').
`longname`	full site name/description.
`country`	country of origin for site.
`lat`	latitude.
`long`	longitude.
`MAT`	mean annual temperature (°C).
`MAP`	mean annual precipitation (mm).
`IGBP`	International Geosphere–Biosphere Programme land classification code (forests ONLY).