Define and document an API

[korsbo]

Before the release of 1.0, there must be a clear demarcation of what is or is not part of the API. This is especially needed for other packages which have latexify as a dependency and which use the @latexrecipe macro. SemVer is useless if nothing is considered part of the API and it is crippling if the API includes everything.

Clearly part of the API:

• latexify
• The support and defaults of latexify for all different kinds of input types or combinations thereof.
• Keyword arguments and their default values.
• The intended output of latexify. env=:align gives a latex align environment, ect. The general form of the output string.

Less clear:

• The exact output string of a call.

A few spaces here or there or whether something is surrounded by \mathrm{} should not matter too much for users. Having this exact string be a part of the API means that every little enhancement to the output would be a breaking change and requires a major version bump. This would slow down such enhancements greatly. However, not having in the API makes testing very difficult which is a problem for anyone relying on a @latexrecipe.