Minijinja

- Remove internal refcounts from environment.
- Changed `Object` and `FunctionArgs` interface to take
arguments by reference. (101)
- `sync` mode is now always enabled. (104)
- Removed meta API. (105)
- Error no longer implements `PartialEq`.
- Simplified the function interface. Filters, tests and global
functions can now directly return values instead of results. (107)
- MiniJinja no longer silently iterates over non iterable values.

Breaking Changes

- The `meta` API is gone without replacement.
- `Object::call_method` and `Object::call` now take the arguments
as `&[Value]` instead of `Vec<Value>`.
- `Object::call_method`, `Object::call` and `FunctionArgs::from_values`
now take the arguments as `&[Value]` instead of `Vec<Value>`.
- The error object used to implement `PartialEq` but this was implemented
by comparing the error kind instead. Explicitly use the `.kind()`
method of the error if you want the same behavior.
- `DebugInfo` is no longer exposed. This might come back if a better
API can be found.

- Fixed binary subtraction operator requiring a space. (94)
- Fixed trailing commas not working in function calls. (95)

- Small internal improvements to context creation. (79)
- Add support for JSON/YAML/JavaScript Escaping. (82)
- Add missing escape support for single quotes (`'`). (81)
- Added support for newlines in string literals. (85)
- Added support for block assignment syntax. (86)
- Added string concatenation with `+` for Jinja compat. (87)
- Enable debug mode by default in debug builds. (88)
- Added `render!` macro and `render_str`. (89)
- Fixed an issue where trailing whitespace removal did not work on blocks. (90)
- Added `loop.changed()` method. (91)

- Fixed a bad dependency declaration.

- Improved debug printing of context.
- Added `-`, `_` and `.` to set of unescaped characters in `urlencode`. (72)
- Bumped `v_htmlescape` dependency. (74)

- Added support for `{% raw %}`. (67)
- Minimum Rust version moved up to 1.45.
- Added support for `{% set %}`. (70)