[RaghuMalayalam] port to mlm2 spec

Signed-off-by: Rajeesh K Nambiar <rajeeshknambiar@gmail.com>
1. Add empty lookup tables for mlm2 (akhn, pref, pstf, pres)
   and combine mlym/mlm2 lookups (blws, psts)
2. Run sed scripts on RaghumalayalamSans.sfd as outlined below to add mlm2 lookup rules
   #mlym akhn to mlm2 akhn
   sed -i "s/\(Ligature2: \"'akhn' Akhand in Malay+AQEA-lam lookup 0 subtable\"\)\(.*\)/&\nLigature2: \"'akhn' Akhand in Malay+AQEA-lam2 lookup 0 subtable\"\2/g"

   #mlym pres to mlm2 akhn
   sed -i "s/\(Ligature2: \"'pres' Pre Base Substitutions in Malay+AQEA-lam lookup 7 subtable\"\)\(.*\)/&\nLigature2: \"'akhn' Akhand in Malay+AQEA-lam2 lookup 0 subtable\"\2/g"

   #replace the half forms variants with virama from above step
   sed -i "/Akhand in Malay+AQEA-lam2/{s/_uni0D4D/ uni0D4D/}"
   #remove unnecessary akhn rules for Ra (0D30) and La (0D32) from above step
   sed -i "/Ligature2: \"'akhn' Akhand in Malay+AQEA-lam2 lookup 0 subtable\".*uni0D30.*/d"
   sed -i "/Ligature2: \"'akhn' Akhand in Malay+AQEA-lam2 lookup 0 subtable\".*uni0D32.*/d"

   #mlym pres to mlm2 pres for Ra
   sed -i "s/\(Ligature2: \"'pres' Pre Base Substitutions in Malay+AQEA-lam lookup 7 subtable\" \)\(.*\) uni0D30.pb/&\nLigature2: \"'pres' Pre Base Substitutions in Malay+AQEA-lam2 lookup 7 subtable\" uni0D30.pb \2/g"
3. Add akhn rules for യ്യ and വ്വand chillus
[smc/fonts] Adding test case for Samavruthokaram

Added test cases for samvruthokaram.