Pyevmasm

The release of pyevmasm 0.2.3 includes the following changes:
* Bug fix: Correct an error with a staticmethod called by the `name` property of the `Instruction` class
* Numerous code cleanups and linting corrections
* Additional type annotations

The release of pyevmasm 0.2.2 includes the following changes:
* Support for new opcodes with Istanbul fork
* Code cleanup with more consistent code style
* Improve gas accuracy

The release of pyevmasm 0.2.1 that includes the following changes:

* The default fork is now St. Petersburg ("petersburg" in code)
* Increased performance for instructions semantics
* Fix LOG and DUP instruction assembling (Thanks f0rki!)
* Improved roundtrip assembly/disassembly test (Thanks f0rki!)
* Improve accuracy of instruction semantics for instructions that read or write memory
* Improve gas accuracy

We are excited to release pyevmasm 0.2.0 that includes the following changes:

* Added assembling and disassembling support for every fork: frontier, homestead, tangerine_whistle, spurious_dragon, byzantium, constantinople, and serenity
* Improved usability with more accurate errors and help text
* Improved gas accuracy

This release includes more accurate gas costs for instructions and an updated readme.

Initial release