Allow symbol removal from VST in VST Maker

[subins2000]

VST Maker should allow to remove a symbol from VST using a matching condition. In Malayalam scheme:

anusvara [["m"]] => ["ം","ം","മ"]
anusvara "m_" =>  ["ം","ം","മ"]
anusvara({:accept_if => :ends_with}, "m" => ["ം","ം","മ"])
anusvara({:accept_if => :in_between}, "m" => ["ം","ം","മ"])

consonants ["ma"] => "മ"

generate_cv

The CV generation makes m => മ് but there is no use of മ് at the end of a string, anusvara will be used instead. So, need to remove the generated m => മ് and then custom add it:

anusvara({:accept_if => :starts_with}, "m" => ["മ്"])
anusvara({:accept_if => :in_between}, "m" => ["മ്])