6.4.0: Argument encoding

• Merged PR #41: Made argument encoding compatible with new XP runners:
  The default is to encode them binary-safe using utf-7. Only difference:
  Passing "utf-8" as encoding value will prevent any decoding from happening.
  (@thekid)

6.3.1: Boostrapping

• Merged PR #39: Refactor bootstrapping to match precedence definitions
  (@thekid)

6.3.0: Class path precedence

• Merged PR #39: Refactor bootstrapping to match precedence definitions
  (@thekid)

6.2.0: Run xar files

• Removed deprecation warning with "iconv.internal_encoding". See the PHP
  RFC https://wiki.php.net/rfc/default_encoding
  (@thekid)
• Merged PR #38: Implement running .xar files directly without xp.runtime.Xar,
  e.g. xp test.xar. Works with all XP 6 releases, XP 7.0-dev & XP 5.12.
  (@thekid)

6.1.0: Run class files

• Merged PR #37: Implement running class files by their file name, e.g.
  xp Test.class.php. Works with all XP 6 releases, XP 7.0-dev & XP 5.12.
  (@thekid)

6.0.0: Modules

• Adopted xp-framework/rfc#300 and switched to semantic versioning
  (@thekid, @kiesel)
• Implemented xp-framework/rfc#306: Load modules, see PR #36.
  (@thekid)
• Allowed empty ini keys, treat them the same as being absent
  (@thekid)

5.7.2: Remove deprecation warning

• Changed code to no longer set iconv.internal_encoding which is
  deprecated
  (@thekid)

5.7.1: Use Jessie

• Switch Debian distribution to jessie
  (@mikey179)

5.7.0: Debian package

• Merged PR #34: Automatically create Debian package and publish to Bintray
  (@mikey179, @thekid)

5.6.1: Startup errors

• Merged PR #33: Display startup errors with stack traces
  (@thekid)