Python-redmine

- Fixed: Issue 39 (It was impossible to save custom_fields in User resource via `new()` method)

- Added: ResourceSet's `get` method now supports a `default` keyword argument which is returned when a requested Resource can't be found in a ResourceSet and defaults to `None`, previously this was hardcoded to `None`
- Added: It is now possible to use `getattr()` with default value without raising a `ResourceAttrError` when calling non-existent resource attribute, see Issue 30 for details (thanks to [hsum](https://github.com/hsum))
- Fixed: Issue 31 (Unlimited recursion was possible in some situations when on demand includes were used)

- Added: New exceptions:
- RequestEntityTooLargeError
- UnknownError
- Fixed: Issue 27 (Project and Issue resources `parent` attribute was returned as a dict instead of being converted to Resource object)

- Added: Introduced the detection of conflicting packages, i.e. if a conflicting package is found (PyRedmineWS at this time is the only one), the installation procedure will be aborted and a warning message will be shown with the detailed description of the problem
- Added: Introduced new `_Resource._members` class attribute where all instance attributes which are not started with underscore should be listed. This will resolve recursion issues in custom resources because of how `__setattr__` works in Python
- Changed: `_Resource.attributes` renamed to `_Resource._attributes`
- Fixed: Python Redmine was unable to upload any binary files
- Fixed: Issue 20 (Lowered Requests version requirements. Python Redmine now requires Requests starting from 0.12.1 instead of 2.1.0 in previous versions)
- Fixed: Issue 23 (File uploads via `update()` method didn't work)

- Fixed: Issue 19 (Resources obtained via `filter()` and `all()` methods have incomplete url attribute)
- Fixed: Redmine server url with forward slash could cause errors in rare cases
- Fixed: Python Redmine was incorrectly raising `ResourceAttrError` when trying to call
`repr()` on a News resource

- Fixed: Issue 16 (When a resource was created via a `new()` method, the next resource created after that inherited all the attribute values of the previous resource)