voices: support a maintainer annotation in voice files

CHANGELOG.md

 *  Group languages by their language family and use BCP47 compliant names.
 *  Support for Windows and BSD platforms.
 *  Removed support for WinCE, MS-DOS and RiscOS.
+*  Add support for a `maintainer` field in voice files for tracking voice
+   maintenance.
 
 build:
 

docs/voices.md

   - [name](#name)
   - [language](#language)
   - [gender](#gender)
+- [Maintenance Attributes](#maintenance-attributes)
+  - [maintainer](#maintainer)
 - [Voice Attributes](#voice-attributes)
   - [pitch](#pitch)
   - [formant](#formant)
 *  \<gender\> may be male, female, or unknown.  
 *  \<age\> is optional and gives an age in years.
 
+## Maintenance Attributes
+
+### maintainer
+
+	maintainer <maintaner>
+
+Specifies the person responsible for updating the voice and associated language
+files. If no maintainer is specified, the voice does not currently have an
+active maintainer.
+
 ## Voice Attributes
 
 ### pitch

src/libespeak-ng/voices.c

 	V_PHONEMES,
 	V_DICTIONARY,
 
+	V_MAINTAINER,
+
 	// these affect voice quality, are independent of language
 	V_FORMANT,
 	V_PITCH,
 	{ "language",     V_LANGUAGE },
 	{ "gender",       V_GENDER },
 
+	{ "maintainer",   V_MAINTAINER },
+
 	{ "formant",      V_FORMANT },
 	{ "pitch",        V_PITCH },
 	{ "phonemes",     V_PHONEMES },
 					fprintf(stderr, "dictdialect name '%s' not recognized\n", name1);
 			}
 			break;
+		case V_MAINTAINER:
+			break;
 		default:
 			if ((key & 0xff00) == 0x100)
 				sscanf(p, "%d", &langopts->param[key &0xff]);