add string features lua example

examples/undocumented/lua_modular/features_string_char_modular.lua

@@ -0,0 +1,25 @@
+require 'shogun'
+require 'load'
+
+strings = {'hey','guys','i','am','a','string'}
+parameter_list={{{strings}}}
+
+function features_string_char_modular(strings)
+
+	f=StringCharFeatures(strings, RAWBYTE)
+
+	print("max string length" ..f:get_max_vector_length())
+	--print "number of strings", f:get_num_vectors()
+	--print "length of first string", f:get_vector_length(0)
+	--print "strings", f.get_features()
+
+	f:set_feature_vector({'t','e','s','t'}, 0)
+
+	print ("strings" .. f:get_features())
+	return f:get_features(), f
+end
+
+if debug.getinfo(3) == nill then
+	print 'StringCharFeatures'
+	features_string_char_modular(unpack(parameter_list[1]))
+end