Another bunch of edits

Features some bug fixes plus:

## Full two-way support for metadata

just put a YAML-like header in your markdown file 
```yaml
---
title: Title
tags: list, of, tags
notebook: Notebook name
---
Contents
```
and send/update to evernote commands will respect the info.
The open command produces the header for imported notes.

## Inline css

some tags can be styled (with inline style attributes). This required a small patch in `markdown2.py`.