tmpDir specification should allow to be without trailing slash

Given:

I define tmpDir like "C:\temp" or /tmp

Then:

Droidium creates a temp directory like C:\temp-1223-1454-1245-12545

Expect:

I expect directory to be rather C:\temp\1223-1454-1245-12545

Current behavior is problematic as it requires user to be slash aware as otherwise he might want to create a directory in tree hierarchy where elevated permissions are needed.

Implemenation note:

new File(File parent, String childPath) would be the best way how to handle this.