Adding RLE-core module for JPEG encoder

> This includes the addition of **RLE module to the JPEG encoder** with Test Bench : 
> 
> **RLE module** : 
> The module takes an input_data and generate an output compressing all the zeros within two non-zero values in the form of runlength, which is used to compress the image.
> **RLEmain.py** : 
> Connect the input to both the RLEcore and the Entrophycoder.
> **RLEcore.py** : 
> Takes the input and calculate the runlength that is number of zeros between two non-zero values.
> **Entrophycoder.py** : 
> Takes the input of the non-zero amplitude and calculate the number of bits required to store that amplitude.
> 
> **Test Bench** : 
> new_rlemain_tb.py
> new_entrophycoder_tb.py
> new_rlecore_tb.py
> This three modules are made for the testing of the RLEmain, Entrophycoder and RLEcore respectively.
> 
> **Common.py** : 
> Added input_data for testing the RLE module and various functions such as setdata() to get the input and output in the required format.
> 
> After adding the above changes, the resultant repository contains the **working model of the RLE module along with the test suite**.