Work around compiler crash due to missing 'env' (before declaration analysis) when combining @ccall with argument annotations.

Allow arbitrary type references in annotations, rather than just valid executable Python expressions.

Disable an "embedsignatures" test that is not actually valid with PEP 484 but fails to compile as the return type now interpreted as a C-tuple of Python objects (which is not supported).

Change annotation typing directive to cover all type annotations and modify annotation parsing to be more PEP 484 compatible.
Only "cython.*" types are interpreted as C types from now on, everything else is considered Python types for maximum compatibility with Python type hints.

Also parses variable annotations as type declarations.
Closes #1850.

Closes #1831.

Use potentially faster PyObject_Malloc() instead of C malloc() for strides and format fields in ndarray buffer support.

Make tracing tests work exactly as in CPython and compare the tracing results for both Python and Cython functions.
Fix "frame.f_trace" test in tracing code accordingly.
See #1769 and #1774 for background.

Better fix for #1836: set frame flags to make CPython create a new dict for "frame.f_locals" at need.

Pass am empty dict instead of a f_globals reference to profilers.

See #1774.

Fix "NoneType object is not callable" exception when using a tracing …

travis: disable dependency installation in "-dev" Python builds (currently fails for Py3.7, and might fail again in the future).

Partial workaround for Github Issue #1852.

Evaluate and join more f-string constants at compile time, including unprefixed strings.
Fix a case where f-string constants could have incorrect constant compile time result values, thus leading to incorrect comparisons and constant folding errors.

Implement two more special cases in fstring joining to reduce the need for runtime character size detection.

Add wheelhouse directories to gitignore.