Updated README, demo notebook, version info (1.4) (#71)

* Removed executable portion of beta_functions.py

This section was never used and very out of date. Removing it.

* modified:   notebooks/CSU_RadarTools_Demo.ipynb

* modified:   notebooks/CSU_RadarTools_Demo.ipynb

* Rename test file to the proper, expected name

* Drop EoL Python 3.4 from active test matrix and add current 3.7

* Minor refactoring that *should* streamline installing the test environment.

* update demo notebook

* modified:   README.md
	modified:   csu_radartools/_version.py
	modified:   setup.py

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Co-authored-by: C.A.M. Gerlach <widenetservices@gmail.com>

Further fix/improve setup.py, add RELEASE.md, update README and CHANG…

…ELOG, and final cleanup for release (#62)

* Improve handling of USE_CYTHON and Numpy/Cython not being availible

* Add build requirements to pyproject.toml

* Rename USE_CYTHON to CSURT_F2PY to avoid conflicts and be cleaner

* Major updates to README and conform to proper Markdown format

* Centralize version handling and make top-level setup constants caps

* Add release instructions

* Update CHANGELOG with new changes since Github release

Merge pull request #50 from tjlang/master

Example notebook updates

Merge pull request #50 from tjlang/master

Example notebook updates

Merge pull request #50 from tjlang/master

Example notebook updates