Supporting Arrays and Allocatables in LFortran

This project aims to add support for arrays and allocatables in LFortran. Specifically, features to be added for arrays are as follows,

• Declaring Arrays
• Operations on Arrays
• Indexing Arrays
• Passing Arrays as Functions/Subroutines Arguments
• Array Initializer Expressions
• Slicing Arrays
• Intrinsic Functions for Arrays

For supporting allocatables, the main focus would be on generating instructions to allocate memory in heap using malloc. There are some miscellaneous goals as well, such as improving support for pointers and kinds and some bug fixes discovered along the way.