Add support for scripts under bin

Add support for scripts under bin
Improvement for exec, packages with not upstream git repo

Introduce python_modules with symlinks under it maintained

PYTHONPATH is now shortened, to only list python_modules under each epm home.
And python_modules will have symlinks to root artifacts under each local package's host.py maintained.

Generation of cabal.project and stack.yaml can be avoided now

By touching a file named avoid-cabla.project at root of an epm home directory, then cabal.project will not be automatically generated there; avoid-stack.yaml will work the same way.

Preliminary Python support

epm exec now composes PYTHONPATH from local packages

Haskell Project moved into edh-universe subfolder

In 0.1.6 and before, epm maintains the Cabal/Stack project at top level of an EPM home, so dist-newstyle and .stack-work will be generated there too when building.

Since 0.1.7 on, the project artifacts (i.e. cabal.project and stack.yaml) are maintained under edh-universe, keeping EPM home clean at top level.

Improved Documentation

Improved Documentation

Allow EPM home initialization with packages

Allow EPM home initialization with packages

Improve Cabal Support

Improve Cabal Support

Bugfix Release 0.1.3

Bugfix Release 0.1.3

Bugfix Release 0.1.2

Bugfix Release