vimlight 0.19

• viewport: only show highlights of text inside current screen. Blazing fast to view large files now!
• lots of improvement in code structure and tidy up
• vim side clean up, better multi-buffer/window support
• functions can be highlighted better
• analyzer refactored. better architecture, more extensible, more maintainable.
• various bug fixes
• highlighting is less messy when inserting/deleting lines
• more (see git log)