support for mb-br2 and mb-br3

dictsource/xex_list

 ku	k%u:_:
 vu	_:v%u:_:
 
-ka	k'a_
-bo	b'o_
+ka	ka_
+bo	bo_

espeak-ng-data/voices/mb/mb-br2-xex

+language xex 4
+name brazil-xextan-2
+gender female
+
+phonemes pt-br
+phonemes pt
+pitch 115 195
+voicing 120
+speed 80
+
+dictrules 2 4
+
+tunes s7 c7 q7 e7
+
+mbrola br2 ptbrxex_phtrans
+

espeak-ng-data/voices/mb/mb-br3-xex

+language xex 5
+name brazil-xextan-3
+gender male
+
+phonemes pt-br
+phonemes pt
+pitch 80 120
+voicing 120
+speed 80
+
+dictrules 2 4
+
+tunes s7 c7 q7 e7
+
+mbrola br3 ptbrxex_phtrans
+