Allow case-insensitive search

[nkakouros]

This is common in applications like vim, less, etc.

[thehunmonkgroup]

I'm in favor of the idea, and, we'd need to figure out how best to implement it:

• VIT's default structure is vim-like
• Among other things, vim allows that via \c, \C, and the ignorecase and smartcase settings
• However, VIT is designed to support other keyboard configurations, so my preference is to avoid hard-coding things to expect the vim approach

Thoughts?

[scottkosty]

I agree it would be nice to have. I'm not sure what the best interface is.

[ahillio]

It'd be really sweet to have vim's smartcase setting :)

[nfraprado]

I think ignorecase and smartcase configurations are a must-have.
Being able to override this configuration for a single search also seems useful. I don't really like the \c and \C solution, which would require the search text to be parsed for this special sequence, but I couldn't think of a better one either.
Other options would be having commands for case-insensitive searches (SEARCH_FORWARD_INSENSITIVE, SEARCH_REVERSE_INSENSITIVE, or for NEXT and PREVIOUS), or a command that sets case-insensitivity until it is disabled. But \c and \C still seem a better option.

I couldn't resist implementing the ignorecase and smartcase configurations here. It got me thinking if instead of these two separate configurations, which are really three possible values, couldn't it be a single casemethod configuration with sensitive, insensitive and smart as possible values. It would eliminate the weird case where ignorecase and smartcase can both be used in the configuration.