made usage example show more diverse examples.

Added nearly exhaustive conversion checks for each type and added tes…

…ts (#4)

* started creating tests, fixed spelling, and started fixing convertible fn

* huge update to checking convertibility between pointer types

* finished extensive isConvertibleTo tests

* pointers fixed

* fixed case for overloading with function that has void argument.

* Updated usage text to include instructions for single void argument functions

Update build.zig.zon version

Update README.md install instructions