Add, change, and fix macros

[Mathman2028]

New macros:

• find: finds the first index where some substring occurs in another string
• count: counts the number of times some substring occurs in another string Updated macros:
• add, multiply, and, or now support infinite arguments
• changed base error message in error and assert Bug fixes:
• escaping the brackets in macros now works properly
• json macros now escape the brackets in their arrays to prevent those macros being parsed

[Mathman2028]

there seems to be an inconsistency with how you're doing custom errors one of them uses a new class, and one of them uses a boolean on the old class, and it seems that the code is generating one but checking for the other

the macros error and assert raise the CustomMacroError, which is then caught in the macro error handler (macros.py, line 428)

that then sets the boolean for FailedBuiltinMacro which is handled by the default handler (errorhandler.py, line 203)