Systemrdl-compiler

**New Features**
- Add `RootNode.top` property to simplify access to top-level `addrmap` component
- Add mechanism to override implicit default property value when calling `Node.get_property()`
- Allow access to more Perl constructs in preprocessor (10)
- Add implementation of RDLFormatCode processing.
- See `Node.get_html_desc()`
- Also enhanced to allow Markdown syntax in `desc` properties

**Bug Fixes**
- Fix default value getter for 'name' property

**New Features**
- Implemented preprocessor
- Supports Verilog-style `` `include "file"`` directive and embedded ``<% Perl code %>`` tags.
- Implemented property references in RHS expressions.
- Implemented optional compiler warning messages.
- Add ability to define built-in user-defined properties.
- Reworked error context message printing mechanism.
- Implemented `__repr__()` to some types to provide more useful debug printing. (5)

**Bug Fixes**
- Fix error message color output in Windows cmd shell. (9)
- Fix error handling on lexer token recognition exception. (2)
- Fix UTF-8 support. (1)

Initial Release