Bugfixes/consistency improvements for multiline stuff

[thomcc]

• Movement::{BeginningOfLine,EndOfLine,etc} now actually go to beginning/end of the line.
• Movement::BeginningOfBuffer, etc was added to get the original functionality back.
• Fix some off-by-one bugs in the line movement code.
• Make it easier to test the multiline functionality by adding a matching bracket validator, and using it in the examples.

[gwenn]

zsh seems to escape only '\n':

echo "\test\
t"
echo "\test\\
t"

[gwenn]

But zsh is buggy if line ends with a backslash:

$ echo test\\
$ # a space is appended in history 

[thomcc]

That part is just so that if you have a multiline history item, after saving/loading it doesn't come back as individual lines.

Edit: Ah, nevermind, I misunderstood your point. I can rebase this this weekend.

[gwenn]

With bash, Ctrl-A/Ctrl-E|Ctrl-U/Ctrl-K moves|kills to begin/end of buffer even with multiline input.
Maybe we should keep the current behaviour ?

[thomcc]

It's a mix with what does what -- fish-shell and... every text editor supporting these have it go to the beginning of the line.

Also, as an anecdote: I use these very commonly and find going to the beginning of the buffer very frustrating (as it behaves differently than text editors).

[gwenn]

Ok.

[tailhook]

Anything left for this PR to get merged (except resolving conflicts of course)? We already use the code from the branch, and are pretty happy with it.

[thomcc]

Sorry, I was mistaken that I'd have time last weekend, but I have nothing else planned for this weekend/tomorrow afternoon and will rebase it.

[thomcc]

This should be good now.

[gwenn]

Thanks.