Merge pull request #1 from ayoshiaki/master

Update
Merge pull request #21 from danielvfo/master

Correção de encapsulamento dos objetos venv e tenv da classe Env.
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Merge pull request #17 from eduardohk/master

Implementação dos métodos abstratos em Canon.java e RelCx.java
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Correção das classes CALL.java e CONST.java
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Merge pull request #18 from marimiglionari/master

Correção das classes CALL.java e CONST.java
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Implementação das classes ESEQ.java e EXPR.java
Merge pull request #19 from helderhp/master

Implementação das classes ESEQ.java e EXPR.java
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Implementação das classes JUMP.java e LABEL.java