Adding custom library functions to the design

A custom library was made as a collection of internal basic data types and conversion routines, memory read/write functions and procedures. The library can be found under Hastlayer.ip\Hast. If you want to use the functions of this library in a custom IP, you have to add the sources you find in this library to the project, and set the library name to Hast (default is xil_defaultlib).