- Add options to Markdown mode to make it easier to extend
- Add GFM text overlay
  - SHA, User@SHA, and User/Project@SHA
  - #Num, User/#Num, and User/Project#Num
  - Vanilla URLs
- Add GFM-specific tests
- Fix overlay code so blankLine() is called
- Fix GFM for v3

- Inline links (square brackets followed by parentheses) cannot be separated by space (per Documentation and Dingus).

- Added test that checks both for this and correct highlighting of square brackets by themselves.

Also avoid a global variable that snuck through.

To make it easier for themes to override it.

Fixes ambiance

Closes #855

This'll align them with the previous line. It's not a perfect solution,
but probably better than simply returning 0.

Issue #854

fix reverse Regexp match which cause memory leak

Closes #844

Closes #843

Closes #853

It would not propertly update the gutter width.

The line calculation was ignoring paddingTop and scrolling.

Should help trigger #836, and is cleaner anyway.

Closes #840

When the editor is hidden, they can be null.

I don't know what they were thinking, but this, on
recent Opera versions, seems to give the correct
result.

Closes #10

Closes #745