config.ps1 moved to code, basic support for profiles

These commits address the issues discussed in #230:
- config.ps1 isn't used anymore to set aliases
- the InitialSessioState.CreateDefault() is used for all basic aliases, functions and variables
- It's always used, even when used with API
- We have first support for user profiles. Currently only CurrentUserCurrentHost is support, but the code is easily extendable. I decided to put the windows user profile to MyDocuments\Pash_profile.ps1, similar to where PS expects it. On unix systems it's current looked for at ~/.Pash_profile.ps1, because that's the native unix behavior for such things.