noincsearch by default

[willzhang100]

I work with a codebase with long function and class names, many of which are similarly named (beginning with the same prefix). When incsearch is set by default, the cursor is often set to the incorrect variable as I type. Then there are times when I forget exactly how the variable is named as I am typing it. This setting may be useful to other people but it frustrates me more often than not