v0.8.0

Changelog:

• Change log(x) to be base 10 by default. Other bases can be specified using log(x, b) or the natural logarithm with ln(x).
• Support for abbreviated inverse trig function names: asin(...) etc.
• Add a "syntax_error" key to the result dictionary, if the input test string contains invalid syntax.
• Better replacement of Unicode characters based on their names.
• Fix an issue where 2l or 2L was interpreted as a numeric long, not as multiplication of a symbol.
• Rename result keys to be consistently in snake_case.