Packtype

* Added support for rendering multiple templates for one language type
* Moved pack/unpack function definitions into a separate `.cpp` file for C++
* Moved pack/unpack function definitions into a separate `.c` file for C

Fixing missing newline at end of SystemVerilog output causing lint failures

Fixing issue with field ordering in SystemVerilog template.

Adding the ability to pack structs from MSB - also adding a template to generate HTML documentation.

python
import packtype
from packtype port Scalar, Struct

packtype.struct(width=32, pack=Struct.FROM_MSB)
class MyStruct:
field_a : Scalar(width=8, desc="Will be positioned at bit 24")
...

Including templates in Python package so that tool can render code.

First release of Packtype to GitHub and PyPI:

https://pypi.org/project/packtype/