Migration warnings:

• You will need to modify all occurrences of FolderDaemon with the new syntax shown in the docs
• The namespace of a few functions has changed (see changes)

Added functions:

• filesystem.exists() to provide a reimplementation to fs' deprecated exists() function (#14)
• filesystem.ensureDirs() to ensure a set of directories exists (#18)
• filesystem.ensureDirsSync() as a synchronous counterpart to ensureDirs() (#18)
• system.usedHeap() to get the current heap usage in percent (#19)

Changes:

• Replaced FolderDaemon's configuration parameters with a single settings object (#13)
• Added base class SCLError to all errors to implement the date property (#17)
• Moved a few functions to the new system namespace:
  • noShutdown() - moved to system
  • yesShutdown() - moved to system
  • softShutdown() - moved to system
  • inDebugger() - moved to system
  • setWindowTitle() - moved to system

Fixed bugs:

• isEmpty() with value null threw a TypeError (#15)
• Package mysql isn't included in the dependencies (#21)
• Definition of system.softShutdown()'s callback function was wrong (#20)