Allow Specifying Entry Point Folder #131

Currently, AZURE_FUNCTIONAPP_PACKAGE_PATH defines both the root folder that will be loaded into the Azure Function and the folder that is the entry point for the function. I have a file structure where the function code requires files higher up in the hierarchy than the function root folder.

As an example, consider this structure below, where function/ refers files in library/. If I specify project/function/ as AZURE_FUNCTIONAPP_PACKAGE_PATH, the folder library/ will not be uploaded.

project
->function
->library

I can work around the problem by changing the structure:

project
->function
->-> library

To avoid using the workaround, it would be nice if a new variable AZURE_FUNCTIONAPP_ENTRY_POINT_PATH was added. This variable would specify the path of the folder where the Azure Function code is defined.