Improve wording on libraries sections in reference

[orta]

re: https://twitter.com/taybenlor/status/497540001639698433

@CocoaPods http://t.co/4y3hkOJny3 I spent a day changing strings until I found out that it expected 'Pod/libMyLib.a'

@orta explain: what it does (adds library search path), what the string is (full path from spec root) and related fields (library)

@orta for those of us working with pods as a black box there's lots of pages for old issues, it's hard to nail down current behaviour

[fabiopelosin]

Podspecs should be located at the root of the repository, and paths to files should be specified relative to the root of the repository as well. File patterns do not support traversing the parent directory ( .. ). File patterns may contain the following wildcard patterns:

from: http://guides.cocoapods.org/syntax/podspec.html#group_file_patterns

[orta]

I think it's useful to have both libraries & vendors_libraries point to each other in the docs, I'm not sure that's instantly apparent.

[fabiopelosin]

👍