Standardize parameters addons for plotting (based on OSGeo#1071 )

Implementing some of the suggestions in issue OSGeo#1071

Question is how to deal with backward compatibility.

src/temporal/t.rast.boxplot/t.rast.boxplot.py

@@ -103,7 +103,7 @@
 # %end
 
 # %option
-# % key: font_size
+# % key: fontsize
 # % type: integer
 # % label: Font size
 # % description: Font size of labels
@@ -667,7 +667,7 @@ def main(options, flags):
     lazy_import_py_modules()
 
     # Plot format options
-    plt.rcParams["font.size"] = int(options["font_size"])
+    plt.rcParams["font.size"] = int(options["fontsize"])
     grid = flags["g"]
 
     # Get range (if defined)

src/vector/v.boxplot/v.boxplot.py

@@ -40,7 +40,6 @@
 # %end
 
 # %option G_OPT_F_OUTPUT
-# % key: plot_output
 # % required: no
 # % guisection: General
 # %end
@@ -106,7 +105,7 @@ def main():
     vector = options["map"]
     column = options["column"]
     group_by = options["group_by"] if options["group_by"] else None
-    output = options["plot_output"] if options["plot_output"] else None
+    output = options["output"] if options["output"] else None
     where = (
         options["where"] + " AND " + column + " IS NOT NULL"
         if options["where"]

src/vector/v.histogram/v.histogram.py

@@ -30,7 +30,6 @@
 # %option G_OPT_DB_WHERE
 # %end
 # %option G_OPT_F_OUTPUT
-# % key: plot_output
 # % label: Name for graphic output file for plot (extension decides format, - for screen)
 # % required: yes
 # % answer: -
@@ -58,7 +57,7 @@ def main():
     layer = options["layer"]
     column = options["column"]
     bins = int(options["bins"])
-    plot_output = options["plot_output"]
+    plot_output = options["output"]
     where = options["where"] if options["where"] else None
 
     if where:

src/vector/v.scatterplot/v.scatterplot.py

@@ -22,7 +22,6 @@
 # %end
 
 # %option G_OPT_V_MAP
-# % key: map
 # % label: Input map
 # % description: input vector layer
 # % required: yes
@@ -57,7 +56,6 @@
 # %end
 
 # %option G_OPT_F_OUTPUT
-# % key: file_name
 # % label: Name of the output file (extension decides format)
 # % description: Name of the output file. The format is determined by the file extension.
 # % required: no
@@ -603,7 +601,7 @@ def main(options, flags):
     # Plot parameters & aesthetics
     plot_dimensions = [float(x) for x in options["plot_dimensions"].split(",")]
     plot_title = options["title"]
-    file_name = options["file_name"]
+    file_name = options["output"]
     bins = [int(x) for x in options["bins"].split(",")]
     if options["rgbcolumn"]:
         dot_color = rgbcolumn