9.0.0: Drop PHP 5 support

• Implemented xp-framework/rfc#334: Drop PHP 5.6:
  . Heads up: Minimum required PHP version now is PHP 7.0.0
  . Rewrote code base, grouping use statements
  . Converted newinstance to anonymous classes
  . Rewrote isset(X) ? X : default to X ?? default
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8.0.1: XP10, Annotation syntax

• Implemented RFC #335: Remove deprecated key/value pair annotation syntax
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• Made compatible with XP 10 - @thekid

8.0.0: XP9 Compatibility

• Heads up: Removed support for deprecated io.Stream instances
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• Changed Stream(Reader|Writer) constructors to accept io.Channel
  instances as well as io.streams.InputStream.
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• Added constants Image::TRUECOLOR and Image::PALETTE, deprecating
  the global defines with the same name and an IMG_ prefix
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• Heads up: Added forward compatibility with XP 9; dropped PHP 5.5
  support, minimum PHP version is now PHP 5.6.
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7.1.1: Refactor typeof()

• Refactored code to use typeof() instead of xp::typeOf(), see
  xp-framework/rfc#323
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7.1.0: XP8 Compatibility

• Added forward compatibility with XP 8.0.0 - @thekid

7.0.0: XP7 compatibility

• Adopted semantic versioning. See xp-framework/rfc#300 - @thekid
• Added version compatibility with XP 7 - @thekid

6.1.1: XP7 Forward compatibility

• Fix code to use nameof() instead of the deprecated getClassName()
  method from lang.Generic. See xp-framework/core#120
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6.1.0: Welcome, XP 6.5 / PHP 5.5

• Heads up: Changed minimum XP version to run webtests to XP
  6.5.0, and with it the minimum PHP version to PHP 5.5
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• Removed calls to deprecated this() - @thekid
• Removed support for deprecated io.Stream instances - @thekid

6.0.3: Forward compatibility

• Added forward compatibility with XP 6.4.0 - @thekid
• Added preliminary PHP 7 support (alpha2, beta1) - @thekid

6.0.2: Fix support for io.File

• Fixed img.io.StreamReader and img.io.StreamWriter to support io.File
  objects again after XP 6 removed its subclassing io.Stream - @thekid