Metadata for directories and various other bugfixes

Due to an earlier oversight, metadata for directories returned incorrect data. This release fixes that and a few other minor bugs.

Added

• Adds integration tests to validate output against comparable output from LocalAdapter
• Adds various @throws annotations
• Adds timestamps for files and folders

Changed

• Changes minimal support from PHP 5.5 to 5.4 to stay on par with the main FlySystem repository
• Changes the default for file visibility to visible
• Changes guessing MIME type for files to always use the file's content instead of extension to guarantee results are the same across different filesystem adapters

Fixed

• Fixes bug that caused invalid repository names to be accepted (issue #4)
• Fixes bug that caused incorrect Metadata for directory to be returned (issue #6)
• Fixes bug that didn't validate paths ended in a trailing slash (issue #8)
• Fixes bug in permission comparison
• Fixes various links in the README file

Improvements and Unit Tests

Added

• Adds automated checks (a.k.a. unit-tests) for the Adapter, Client and Settings classes.
• Adds various utility files for Travis builds, Coveralls and Composer

Changed

• Makes the PHPUnit configuration more strict
• Renames the Client class to "Api"

First working draft - Read functionality

Added

• Read functionality and Github API authentication have been implemented.