Merge tag '0.5.5' into develop
New release cycle.
Merge tag '0.5.5.1' into develop
Merge tag '0.5.5.2' into develop
Merge tag '0.5.5.3' into develop
Debian: Added support for building repo for factory as well.
Changelog updates
Minor cleanups

* Made constants test directly executable with Python3.
Fix, the "exec" statements needs to handle "None" and "locals()" differently.

* Only when "None" is used, locals should be updated.

* Making the sync back to locals explicit, also allows to optimize
  it away for modules.

* Improved tests so they cover more exec specifics now pass.

* This corrects Issue#154.
Cleanups

* Introduce a decorator to deal with built-in name collisions, it now
  automatically renames arguments as they come in to a suffix. This
  avoids the need for using built-in names as arguments when providing
  signatures matching to built-ins which do this a lot.

* Import cleanups.

* Save the closure variable taken by maybe local variables as well.
Cleanups

* Some PyLint stuff.

* Added a few documentations.
Fix handling of maybe closure variables.

* Improves the SSA tracing of affected variable too. We are not using
  the global variable traces yet, but for maybe local variables so far
  they were not getting a usage trace from the maybe local variable
  access.

* Also cleans up code generation, which was hard wired to globals and
  repeating itself there. Not the maybe path is generated via proper
  call to code generation too, without repeating the access to the
  global.

* It's a bit unfortunate that we don't know what "needs_check" for the
  maybe case will be. But it doesn't seem important now.

* This corrects Issue#150.
README.rst: Small typo fix.
Changelog updates
More user and developer manual updates.
Minor cleanups
Fix, may not optimize away checking truth value of conditions of empty branches.

* Found while updating the User Manual, describing the unallowed
  optimization.

* Added test to cover this.
Minor cleanups
Fix, cannot assume that this will always be a source code collector.

* We also provide simple "append" to this in some cases.

* The issue was introduced with C-ish, but only shows with optimization
  added later.
Fix, do not use "replaceWith" on nodes, that are potentially no longer in the tree.

* This might have caused corruption of the node tree, but that had not
  been observed so far.

* It's also more explicit about what it's supposed to change, which child
  to update.