Raster library in GRASS7

GIS library has been split into G_() (general routines) and Rast_() (raster-related routines) part. See also GRASS 7 ideas collection.

Progress:

• r38003 - selected fns moved from gislib to rasterlib
• Various fixes: r38005, r38006, r38007, r38008, r38010
• Macros and structure moved to rasterlib in r38136