Added ClassMap interface
Added ArrayClassMap implementation
MappedAutoloader now used ClassMap instances instead of an internal array
Formatting and comment improvments

Work on classmaps for mapped autoloader
Autoloader test runs in a separate process without access to any previous global state to make absolutely sure that no other autoloaders can affect the test outcome.
Updated bootstrap config to exclude vendor directory
Get VFSStream as a dev-requirement
Test suite for FileClassMap
Reworking of autoload classes
Added exclusions for non-testable files
Test suite simplified
Classmap classes updated
Updated Composer JSON file
Added function overrides file for overriding PHP functions that can't easily be used in unit testing
Updated unit test bootstrap
Comprehensive test suite for autoloader class maps