Fixed issue caused by the original fix for #3161, where build and
public headers were included in the Public/Headers/SpecName directory,
even if they were correctly included also in the
Public/Headers/SpecName/FrameworkName directory as the fix for #3161
was addressing. The headers defined in either source_files and
public_header_files will be ignored if they are already included by the
vendored_frameworks.

- Updated banana-lib.tar.gz to include a SubDir/SubBananalib.h in the
Bananalib.framework.

- Updated broken specs because of the new SubDir/SubBananalib.h header,
and also expanded the new vendor spec added for #3161 to include a
validation for the pretense of SubDir/SubBananalib.h.

Fixes #3161

Symlink vendored framework headers into the public headers dir

Fixes #3161

[Travis] Only build master and stable branches

Flush stdin/stderr and wait a bit in `executable`.

This should make it unlikely that we don't catch the full output of
commands we are executing.

[Cache] Recognize incomplete cache for released pods

Even when cached_spec isn't used further with local podspecs, it still must be read from file to verify that it was correctly written before, because that also indicates that the cached pod is valid.

Shares schemes of any development pods.

The current user (`ENV['USER']`) is already the default.

This makes it easier to individually build the product of a development
pod from a checked-in project, e.g. when using the pod-template,
allowing for improved sharing with non-CocoaPods users.

[Doc] Improvements and Rake task to lint with inch