Correct boolean interpretation for config variables

[baco]

Instead of comparing configuration values read from local config files
with integer values 1 or 0, use their boolean interpretation as they can
be directly set to v:true or v:false respectively in config files.

Solves #364

[vigoux]

I think that the == 1 is mandatory here, as VimL functions return an integer.

[baco]

Result may be an integer, but according to documentation, any value other than zero is considered True, and only 0 is considered False:

                                                       exists()                                            
exists({expr})  The result is a Number, which is TRUE if {expr} is                                          
                defined, zero otherwise.

So which integer doesn't really matters, as long as it can be interpreted the same way boolean expressions are interpreted in C language.

Restricting the comparison to == 1 may lead to unexpected behaviors if for instance, on runtime, the exists() function decides to return 2; which according to documentation is also a valid return value when the expression is defined.

[theHamsta]

But 0 is true in Lua. You could do if XX ~= 0

[baco]

But 0 is true in Lua. You could do if XX ~= 0

Ok, true, corrected the PR

[vigoux]

I think the change should be done in get_option so that it returns a boolean if needed, instead of changing the various statements like you did in the first version of the PR.