Start formatting tables with horizontal scroll and fixed-width font

[artbristol]

Followup from discussion on #74

In this approach the note's content is split into alternating table and text (i.e. non-table) content. The tables are then formatted with a fixed-width font, and horizontal scrolling is used to prevent text wrapping (wrapping makes tables basically unusable)

Before merging I'd at least need to address:

• test breakage
• adding more tests
• consider what to do about editing tables
• consider pushing down the parsing of table content into org-java library and storing result of the table/text parsing process in the database

[artbristol]

@nevenz This works better than I expected. Do you think the ability to edit a table nicely is necessary or could we implement this display enhancement first?
Also this PR parses the tables on the UI thread which I thought would be bad, performance-wise, but it seems fine to me.

[artbristol]

@nevenz I added a very bare-bones edit screen. I tried reusing the NoteViewModel but there is still a lot of duplication.
I was planning to add icons on the edit screen for actions like "reformat", "add/delete column", "add/delete row". What do you think?