Added link to nightly feed
Fixed feed link to use redirection
Fixed virtualenv instructions
Removed deprecated files
Mapping struct to _Struct dash type

As Bogdan explained, considering Struct is much more important in Rust
than in other languages, there is a special hidden type _Struct which is
shown red in tree and has higher priority than usual Struct
Dropping shell commands in favour of Python code

- tar has incompatible parameters on OS X and Linux 
  (—options to be precise)
- openssl could be absent at all
Correct work with “spaced” paths in upload
Supporting stability in Rust docs
Logging errors on unexpected HTML
Forgot to iterate over chunks
Added constant type
Guides fixes

Removed deprecated, fixed namings for new
Renaming Index to Overview, minor cleanup
Oops, forgot one more wrapping
More guide renaming