Fix problem with Cargo.toml, make compilation work
Re-use existing `Cell`s during `UIBuffer::fill()`
Add a dirty flag to `Cell`
Update rustbox version
Address comments
Preserve the cursor’s offset when moving to a shorter line
Draw tab characters

Some support for multi-column characters was already added in #29, so this just
utilises that with a few tweaks to support tab characters as well.
Add a test
Fix a crash when moving between lines with multibyte characters
Use 1-based indices for the line/column indicator in the status bar
Added Up/Down movement methods (uses experimental slicing).
Update rustbox version
Merge pull request #47 from P1start/preserve-offset

Preserve the cursor’s offset when moving to a shorter line
Merge pull request #45 from Crespyl/redraw

Don't redraw cells that haven't changed
Merge pull request #48 from P1start/render-tabs

Draw tab characters
Merge pull request #49 from P1start/one-based-position

Use 1-based indices for the line/column indicator in the status bar
Dont use clone when splitting a line
Merge branch 'master' of https://github.com/emctoo/iota into emctoo-master

Conflicts:
	Cargo.lock
Merge branch 'emctoo-master'
Nothing important.
Merge remote-tracking branch 'parent/master'

Conflicts:
	src/iota/buffer.rs