malloc: Switch from i32 to i64
Implement Input-Redirection in Main.java
Implement reading from *.input in IntegrationTests
Create System.readln() declaration
Add readln_helper() in std_llvm_include.ll
Implement Operations.readln()
Test cases for System.readln()
Create System.read() declaration
Add read_helper() in std_llvm_include.ll
Implement Operations.read()
Test cases for System.read()