Multiline input support

[nitzantomer]

The input box should be able to handle multiline input in the following cases:

1. When the enter key is pressed and the last character is \
2. When the enter key is pressed and there shift key is also down
3. When the enter key is pressed and the there's an open quote (') or double quote (")

[nitzantomer]

@creativeChips @amir-arad
WDYT?