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
  (@thekid)

8.0.2: Annotation syntax

• Implemented RFC #335: Remove deprecated key/value pair annotation syntax
  (@thekid)

8.0.1: XP10 compatibility

• Made compatible with XP 10 - @thekid
• Replaced xp::stringOf() with util.Objects::stringOf() - @thekid

8.0.0: XP9 Compatibility

• Heads up: Dropped PHP 5.5 support - @thekid
• Added compatibility with XP 9.0+ - @thekid
• Dropped dependency on xp-framework/security library - @thekid

7.1.0: XP8 compatibility

• Added forward compatibility with XP 8.0.0: Use File::in() instead of
  the deprecated getInputStream()
  (@thekid)

7.0.0: XP7 compatibility

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

6.2.1: XP7 Forward compatibility

• Fix code to use nameof() instead of the deprecated getClassName()
  method from lang.Generic. See xp-framework/core#120
  (@thekid)

6.2.0: Welcome XP 6.5, PHP 5.5

• Heads up: Dropped PHP 5.4 support. Note: As the main source is not
  touched, unofficial PHP 5.4 support is still available though not tested
  with Travis-CI.
  (@thekid)

6.1.0: PHP 7 support

• Added PHP 7 support - @thekid
• Merged PR #2: Use short array syntax / ::class in annotations - @thekid

6.0.2: Forward compatibility

• Added forward compatibility with XP 6.4.0 - @thekid