readdirInclude and readdirExclude should be the same function

[mhkeller]

With the new idea of passing all options as json, this function should be able to take both include and exclude options. The hard part: what to name it? Candidates:

• readdir and readdirSync except this is the exact same as fs and so could be confusing
• readdirMatch and readdirMatchSync is not bad

What do you think @ebrelsford

[mhkeller]

I think readdirFilter and readdirFilterSync could be good.

[mhkeller]

This has been implemented in 1.0.0. See changelog for details