BASIC compatibility

The BASIC compatibility module provides miscellaneous functions that emulate the behaviour of 'classic' BASIC.

The functions in this module have largely been superceded by BlitzMax features such as 'string slicing', and the Find, Replace, Trim, ToLower, ToUpper string methods.

However, for programmers from a classic BASIC background, these utility functions should make the transition to BlitzMax easier.

NOTE: Strings in classic BASIC are '1 based'. This means that the first character within a string is at index 1, the second at index 2 and so on. However, BlitzMax strings are '0 based', meaning the first character is at index 0, the second at index 1 and so on. The Instr and Mid functions in this module retain the '1 based' behvaiour of classic BASIC.