Add back chi as an alias of chi.alt

This is a partial revert of 543a1804e99e0866c9e6d89bce506330365be9e1,
and it keeps the same number of glyph as the output had before that
commit. That is, before there were glyphs "x" and "chi" which were
identical, after this there are "chi.alt" and "chi" which are
identical.

Again, this is done for consistency with the hinted binaries.

res/diacritics.txt

@@ -307,6 +307,7 @@ kgreenlandic=kappa
 o=omicron
 mu=uni03BC
 v=nu
+chi.alt=chi
 iota+dieresis:top=iotadieresis
 upsilon+dieresis:top=upsilondieresis
 o+tonos:top=omicrontonos

res/ot_classes.txt

@@ -137,7 +137,7 @@
     Mu Nu Omicron Rho Tau 
     Upsilon Chi Iotadieresis Upsilondieresis alphatonos 
     epsilontonos etatonos iotatonos upsilondieresistonos kappa 
-    omicron nu chi.alt iotadieresis upsilondieresis 
+    omicron nu chi iotadieresis upsilondieresis 
     omicrontonos upsilontonos omegatonos uni0401 uni0403 
     uni0405 uni0406 uni0407 uni0408 uni040C 
     uni040E uni0410 uni0412 uni0413 uni0415 

src/v2/Roboto_Bold.ufo/glyphs/chi.alt.glif

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <glyph name="chi.alt" format="1">
   <advance width="1081"/>
-  <unicode hex="03C7"/>
   <outline>
     <contour>
       <point x="1099" y="1082" type="line" name="hr00"/>

src/v2/Roboto_Regular.ufo/features.fea

@@ -23,7 +23,7 @@ languagesystem grek dflt;
 @SC_SET2 = [ uni0410.smcp uni0411.smcp uni0412.smcp uni0413.smcp uni0414.smcp uni0415.smcp uni0416.smcp uni0417.smcp uni0418.smcp uni0419.smcp uni041A.smcp uni041B.smcp uni041C.smcp uni041D.smcp uni041E.smcp uni041F.smcp uni0420.smcp uni0421.smcp uni0422.smcp uni0423.smcp uni0424.smcp uni0425.smcp uni0426.smcp uni0427.smcp uni0428.smcp uni0429.smcp uni042A.smcp uni042B.smcp uni042C.smcp uni042D.smcp uni042E.smcp uni042F.smcp uni0490.smcp uni0492.smcp uni0496.smcp uni0498.smcp uni049A.smcp uni049C.smcp uni04A0.smcp uni04A2.smcp uni04A8.smcp uni04AA.smcp uni04AE.smcp uni04B0.smcp uni04B2.smcp uni04B4.smcp uni04B8.smcp uni04BA.smcp uni04BC.smcp uni04BE.smcp uni04D8.smcp uni04E0.smcp uni04E2.smcp uni04E8.smcp uni04EE.smcp I.smcp ];
 
 @UC_SET3 = [ Alpha Alphatonos Beta Chi Delta Epsilon Epsilontonos Eta Etatonos Gamma Iota Iotadieresis Iotatonos Kappa Lambda Omega Omegatonos Omicron Omicrontonos Phi Pi Psi Rho Sigma Tau Theta Upsilon Upsilondieresis Upsilontonos Xi Zeta Nu ];
-@LC_SET3 = [ alpha alphatonos beta chi.alt delta epsilon epsilontonos eta etatonos gamma iota iotadieresis iotatonos kappa lambda omega omegatonos omicron omicrontonos phi pi psi rho sigma tau theta upsilon upsilondieresis upsilontonos xi zeta nu ];
+@LC_SET3 = [ alpha alphatonos beta chi delta epsilon epsilontonos eta etatonos gamma iota iotadieresis iotatonos kappa lambda omega omegatonos omicron omicrontonos phi pi psi rho sigma tau theta upsilon upsilondieresis upsilontonos xi zeta nu ];
 @SC_SET3 = [ Alpha.smcp Alphatonos.smcp Beta.smcp Chi.smcp Delta.smcp Epsilon.smcp Epsilontonos.smcp Eta.smcp Etatonos.smcp Gamma.smcp Iota.smcp Iotadieresis.smcp Iotatonos.smcp Kappa.smcp Lambda.smcp Omega.smcp Omegatonos.smcp Omicron.smcp Omicrontonos.smcp Phi.smcp Pi.smcp Psi.smcp Rho.smcp Sigma.smcp Tau.smcp Theta.smcp Upsilon.smcp Upsilondieresis.smcp Upsilontonos.smcp Xi.smcp Zeta.smcp Nu.smcp ];
 
 @UC_SET4 = [ OE uni0162 uni010A uni0120 uni037F ];

src/v2/Roboto_Regular.ufo/glyphs/chi.alt.glif

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <glyph name="chi.alt" format="1">
   <advance width="1145"/>
-  <unicode hex="03C7"/>
   <outline>
     <contour>
       <point x="1055" y="1082" type="line"/>

src/v2/Roboto_Thin.ufo/glyphs/chi.alt.glif

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <glyph name="chi.alt" format="1">
   <advance width="1050"/>
-  <unicode hex="03C7"/>
   <outline>
     <contour>
       <point x="979" y="1082" type="line"/>