Check: Badly named files (spaces etc)

[davidperezgar]

This check is based in this sentence that we use reviewing plugins:

There are poorly named files in your plugin

Due to the different types of servers people use for WordPress, we do not permit the use of spaces or certain characters in file names, as they would cause conflicts. Related to this, we do not permit filenames with the same names, but using uppercase (or lowercase) to differentiate them, as they are not universally supported.

We have to make a check to see this problem.